diff --git a/server/entity/MediaRequest.ts b/server/entity/MediaRequest.ts
index 4f17c81f6..09f06a879 100644
--- a/server/entity/MediaRequest.ts
+++ b/server/entity/MediaRequest.ts
@@ -12,7 +12,7 @@ import { Permission } from '@server/lib/permissions';
 import { getSettings } from '@server/lib/settings';
 import logger from '@server/logger';
 import { DbAwareColumn, resolveDbType } from '@server/utils/DbColumnHelper';
-import requestLock from '@server/utils/requestLock';
+import requestLock, { userKey } from '@server/utils/requestLock';
 import { truncate } from 'lodash';
 import {
   AfterInsert,
@@ -48,7 +48,14 @@ export class MediaRequest {
     user: User,
     options: MediaRequestOptions = {}
   ): Promise<MediaRequest> {
-    return requestLock.dispatch(requestBody.userId || user.id, () =>
+    // Only a caller allowed to set the request user may queue on their lock
+    const lockUserId =
+      requestBody.userId &&
+      user.hasPermission([Permission.MANAGE_USERS, Permission.MANAGE_REQUESTS])
+        ? requestBody.userId
+        : user.id;
+
+    return requestLock.dispatch(userKey(lockUserId), () =>
       MediaRequest.createRequest(requestBody, user, options)
     );
   }
diff --git a/server/routes/request.test.ts b/server/routes/request.test.ts
index e82a76d24..7273aff91 100644
--- a/server/routes/request.test.ts
+++ b/server/routes/request.test.ts
@@ -21,6 +21,7 @@ import { User } from '@server/entity/User';
 import type { RadarrSettings, SonarrSettings } from '@server/lib/settings';
 import { getSettings } from '@server/lib/settings';
 import { checkUser } from '@server/middleware/auth';
+import { MediaRequestSubscriber } from '@server/subscriber/MediaRequestSubscriber';
 import { setupTestDb } from '@server/test/db';
 import type { Express } from 'express';
 import express from 'express';
@@ -291,6 +292,20 @@ describe('DELETE /request/:requestId', () => {
 
     assert.strictEqual(res.status, 404);
   });
+
+  it('deletes a request once when two deletes race', async () => {
+    const repo = getRepository(MediaRequest);
+    const mediaRequest = await seedRequest();
+    const admin = await loginAs('admin@seerr.dev', 'test1234');
+
+    const results = await Promise.all([
+      admin.delete(`/request/${mediaRequest.id}`),
+      admin.delete(`/request/${mediaRequest.id}`),
+    ]);
+
+    assert.deepStrictEqual(results.map((r) => r.status).sort(), [204, 404]);
+    assert.strictEqual(await repo.count({ where: { id: mediaRequest.id } }), 0);
+  });
 });
 
 describe('PUT /request/:requestId (movie)', () => {
@@ -339,45 +354,70 @@ describe('PUT /request/:requestId (movie)', () => {
   });
 });
 
-describe('PUT /request/:requestId (tv)', () => {
-  it('does not add a season held by another request', async () => {
-    const userRepo = getRepository(User);
-    const mediaRepo = getRepository(Media);
-    const requestRepo = getRepository(MediaRequest);
+async function seedUser(
+  email: string,
+  quotas: {
+    movieQuotaLimit?: number;
+    tvQuotaLimit?: number;
+    tvQuotaDays?: number;
+  } = {}
+) {
+  const userRepo = getRepository(User);
+  const user = await userRepo.findOneOrFail({ where: { email } });
+  Object.assign(user, quotas);
 
-    const owner = await userRepo.findOneOrFail({
-      where: { email: 'admin@seerr.dev' },
-    });
-    const otherUser = await userRepo.findOneOrFail({
-      where: { email: 'demo@seerr.dev' },
-    });
+  return userRepo.save(user);
+}
 
-    const media = await mediaRepo.save(
+async function seedTvMedia(tmdbId: number) {
+  const mediaRepo = getRepository(Media);
+
+  return (
+    (await mediaRepo.findOne({
+      where: { tmdbId, mediaType: MediaType.TV },
+    })) ??
+    (await mediaRepo.save(
       new Media({
         mediaType: MediaType.TV,
-        tmdbId: 67890,
+        tmdbId,
         status: MediaStatus.PENDING,
         status4k: MediaStatus.UNKNOWN,
       })
-    );
+    ))
+  );
+}
 
-    const seedTvRequest = (requestedBy: User, seasons: number[]) =>
-      requestRepo.save(
-        new MediaRequest({
-          type: MediaType.TV,
-          status: MediaRequestStatus.PENDING,
-          media,
-          requestedBy,
-          is4k: false,
-          seasons: seasons.map(
-            (seasonNumber) =>
-              new SeasonRequest({
-                seasonNumber,
-                status: MediaRequestStatus.PENDING,
-              })
-          ),
-        })
-      );
+async function seedTvRequest(
+  requestedBy: User,
+  seasons: number[],
+  { tmdbId = 67890, ignoreQuota = false, createdAt = new Date() } = {}
+) {
+  return getRepository(MediaRequest).save(
+    new MediaRequest({
+      type: MediaType.TV,
+      status: MediaRequestStatus.PENDING,
+      media: await seedTvMedia(tmdbId),
+      requestedBy,
+      is4k: false,
+      ignoreQuota,
+      createdAt,
+      seasons: seasons.map(
+        (seasonNumber) =>
+          new SeasonRequest({
+            seasonNumber,
+            status: MediaRequestStatus.PENDING,
+          })
+      ),
+    })
+  );
+}
+
+describe('PUT /request/:requestId (tv)', () => {
+  it('does not add a season held by another request', async () => {
+    const requestRepo = getRepository(MediaRequest);
+
+    const owner = await seedUser('admin@seerr.dev');
+    const otherUser = await seedUser('demo@seerr.dev');
 
     const mediaRequest = await seedTvRequest(owner, [1, 2]);
     const otherRequest = await seedTvRequest(otherUser, [3]);
@@ -408,6 +448,189 @@ describe('PUT /request/:requestId (tv)', () => {
   });
 });
 
+describe('PUT /request/:requestId (quota)', () => {
+  it('rejects adding seasons beyond the season limit', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('demo@seerr.dev', { tvQuotaLimit: 2 });
+    const mediaRequest = await seedTvRequest(owner, [1, 2]);
+
+    const agent = await loginAs('demo@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [1, 2, 3],
+    });
+
+    assert.strictEqual(res.status, 403);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.deepStrictEqual(
+      saved.seasons.map((s) => s.seasonNumber).sort((a, b) => a - b),
+      [1, 2]
+    );
+  });
+
+  it('rejects adding seasons to a request older than the quota window', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('demo@seerr.dev', {
+      tvQuotaLimit: 2,
+      tvQuotaDays: 7,
+    });
+    const mediaRequest = await seedTvRequest(owner, [1, 2], {
+      createdAt: new Date(Date.now() - 30 * 24 * 60 * 60 * 1000),
+    });
+
+    const agent = await loginAs('demo@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [1, 2, 3],
+    });
+
+    assert.strictEqual(res.status, 403);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.deepStrictEqual(
+      saved.seasons.map((s) => s.seasonNumber).sort((a, b) => a - b),
+      [1, 2]
+    );
+  });
+
+  it('allows swapping seasons at the season limit', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('demo@seerr.dev', { tvQuotaLimit: 2 });
+    const mediaRequest = await seedTvRequest(owner, [1, 2]);
+
+    const agent = await loginAs('demo@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [3, 4],
+    });
+
+    assert.strictEqual(res.status, 200);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.deepStrictEqual(
+      saved.seasons.map((s) => s.seasonNumber).sort((a, b) => a - b),
+      [3, 4]
+    );
+  });
+
+  it('rejects reassignment to a user without room for the existing seasons', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('admin@seerr.dev');
+    const target = await seedUser('demo@seerr.dev', { tvQuotaLimit: 1 });
+    const mediaRequest = await seedTvRequest(owner, [1, 2]);
+
+    const agent = await loginAs('admin@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [1, 2],
+      userId: target.id,
+    });
+
+    assert.strictEqual(res.status, 403);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.strictEqual(saved.requestedBy.id, owner.id);
+  });
+
+  it('rejects reassignment of a movie request to a user at their limit', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const mediaRepo = getRepository(Media);
+
+    const owner = await seedUser('admin@seerr.dev');
+    const target = await seedUser('demo@seerr.dev', { movieQuotaLimit: 1 });
+
+    // Uses up the target's single movie request
+    await seedRequest();
+
+    const media = await mediaRepo.save(
+      new Media({
+        mediaType: MediaType.MOVIE,
+        tmdbId: 55555,
+        status: MediaStatus.PENDING,
+        status4k: MediaStatus.UNKNOWN,
+      })
+    );
+    const mediaRequest = await requestRepo.save(
+      new MediaRequest({
+        type: MediaType.MOVIE,
+        status: MediaRequestStatus.PENDING,
+        media,
+        requestedBy: owner,
+        is4k: false,
+      })
+    );
+
+    const agent = await loginAs('admin@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.MOVIE,
+      userId: target.id,
+    });
+
+    assert.strictEqual(res.status, 403);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.strictEqual(saved.requestedBy.id, owner.id);
+  });
+
+  it('allows reassignment to a user who bypasses quotas', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('demo@seerr.dev', { tvQuotaLimit: 1 });
+    const target = await seedUser('admin@seerr.dev');
+    const mediaRequest = await seedTvRequest(owner, [1, 2]);
+
+    const agent = await loginAs('admin@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [1, 2],
+      userId: target.id,
+    });
+
+    assert.strictEqual(res.status, 200);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.strictEqual(saved.requestedBy.id, target.id);
+  });
+
+  it('allows an edit that exceeds the limit when the request ignores quota', async () => {
+    const requestRepo = getRepository(MediaRequest);
+    const owner = await seedUser('demo@seerr.dev', { tvQuotaLimit: 2 });
+
+    await seedTvRequest(owner, [1, 2], { tmdbId: 77777 });
+    const mediaRequest = await seedTvRequest(owner, [1, 2], {
+      ignoreQuota: true,
+    });
+
+    const agent = await loginAs('demo@seerr.dev', 'test1234');
+    const res = await agent.put(`/request/${mediaRequest.id}`).send({
+      mediaType: MediaType.TV,
+      seasons: [1, 2, 3],
+    });
+
+    assert.strictEqual(res.status, 200);
+
+    const saved = await requestRepo.findOneOrFail({
+      where: { id: mediaRequest.id },
+    });
+    assert.deepStrictEqual(
+      saved.seasons.map((s) => s.seasonNumber).sort((a, b) => a - b),
+      [1, 2, 3]
+    );
+  });
+});
+
 describe('POST /request/:requestId/:status', () => {
   const cases = [
     { action: 'approve', expected: MediaRequestStatus.APPROVED },
@@ -469,6 +692,27 @@ describe('POST /request/:requestId/:status', () => {
     assert.strictEqual(persisted.status, MediaRequestStatus.APPROVED);
   });
 
+  it('applies only one of a concurrent approve and decline', async () => {
+    const repo = getRepository(MediaRequest);
+    const pending = await seedRequest();
+    const admin = await loginAs('admin@seerr.dev', 'test1234');
+
+    const [approve, decline] = await Promise.all([
+      admin.post(`/request/${pending.id}/approve`),
+      admin.post(`/request/${pending.id}/decline`),
+    ]);
+
+    assert.deepStrictEqual([approve.status, decline.status].sort(), [200, 409]);
+
+    const persisted = await repo.findOneOrFail({ where: { id: pending.id } });
+    assert.strictEqual(
+      persisted.status,
+      approve.status === 200
+        ? MediaRequestStatus.APPROVED
+        : MediaRequestStatus.DECLINED
+    );
+  });
+
   it('rejects the removed pending verb even on a non-pending request', async () => {
     const repo = getRepository(MediaRequest);
     const declined = await seedRequest(MediaRequestStatus.DECLINED);
@@ -519,6 +763,29 @@ describe('POST /request/:requestId/retry', () => {
     const persisted = await repo.findOneOrFail({ where: { id: pending.id } });
     assert.strictEqual(persisted.status, MediaRequestStatus.PENDING);
   });
+
+  it('sends a concurrently retried request to *arr once', async (t) => {
+    const repo = getRepository(MediaRequest);
+    const failed = await seedRequest(MediaRequestStatus.FAILED);
+    const admin = await loginAs('admin@seerr.dev', 'test1234');
+
+    const sendToRadarr = t.mock.method(
+      MediaRequestSubscriber.prototype,
+      'sendToRadarr',
+      async () => undefined
+    );
+
+    const results = await Promise.all([
+      admin.post(`/request/${failed.id}/retry`),
+      admin.post(`/request/${failed.id}/retry`),
+    ]);
+
+    assert.deepStrictEqual(results.map((r) => r.status).sort(), [200, 409]);
+    assert.strictEqual(sendToRadarr.mock.callCount(), 1);
+
+    const persisted = await repo.findOneOrFail({ where: { id: failed.id } });
+    assert.strictEqual(persisted.status, MediaRequestStatus.APPROVED);
+  });
 });
 
 describe('DELETE /request/:requestId, deleted media status restoration', () => {
diff --git a/server/routes/request.ts b/server/routes/request.ts
index 9ee569739..270834e24 100644
--- a/server/routes/request.ts
+++ b/server/routes/request.ts
@@ -25,6 +25,7 @@ import { Permission } from '@server/lib/permissions';
 import { getSettings } from '@server/lib/settings';
 import logger from '@server/logger';
 import { isAuthenticated } from '@server/middleware/auth';
+import requestLock, { requestKey, userKey } from '@server/utils/requestLock';
 import { Router } from 'express';
 
 const requestRoutes = Router();
@@ -462,143 +463,200 @@ requestRoutes.put<{ requestId: string }>(
   async (req, res, next) => {
     const requestRepository = getRepository(MediaRequest);
     const userRepository = getRepository(User);
+    const requestId = Number(req.params.requestId);
     try {
-      const request = await requestRepository.findOne({
-        where: {
-          id: Number(req.params.requestId),
-        },
-      });
-
-      if (!request) {
-        return next({ status: 404, message: 'Request not found.' });
-      }
-
-      if (
-        (request.requestedBy.id !== req.user?.id ||
-          (req.body.mediaType !== 'tv' &&
-            !req.user?.hasPermission(Permission.REQUEST_ADVANCED))) &&
-        !req.user?.hasPermission(Permission.MANAGE_REQUESTS)
-      ) {
-        return next({
-          status: 403,
-          message: 'You do not have permission to modify this request.',
+      // Ordering is request then owner here, user then media on create, so no cycle
+      return await requestLock.dispatch(requestKey(requestId), async () => {
+        const request = await requestRepository.findOne({
+          where: {
+            id: requestId,
+          },
         });
-      }
 
-      if (request.status !== MediaRequestStatus.PENDING) {
-        return next({
-          status: 409,
-          message: 'Only pending requests can be modified.',
-        });
-      }
-
-      let requestUser = request.requestedBy;
-
-      if (
-        req.body.userId &&
-        req.body.userId !== request.requestedBy.id &&
-        !req.user?.hasPermission([
-          Permission.MANAGE_USERS,
-          Permission.MANAGE_REQUESTS,
-        ])
-      ) {
-        return next({
-          status: 403,
-          message: 'You do not have permission to modify the request user.',
-        });
-      } else if (req.body.userId) {
-        requestUser = await userRepository.findOneOrFail({
-          where: { id: req.body.userId },
-        });
-      }
-
-      if (req.body.mediaType === MediaType.MOVIE) {
-        request.serverId = req.body.serverId;
-        request.profileId = req.body.profileId;
-        request.rootFolder = req.body.rootFolder;
-        request.tags = req.body.tags;
-        request.requestedBy = requestUser as User;
-
-        await requestRepository.save(request);
-      } else if (req.body.mediaType === MediaType.TV) {
-        const mediaRepository = getRepository(Media);
-        request.serverId = req.body.serverId;
-        request.profileId = req.body.profileId;
-        request.rootFolder = req.body.rootFolder;
-        request.languageProfileId = req.body.languageProfileId;
-        request.tags = req.body.tags;
-        request.requestedBy = requestUser as User;
-
-        const requestedSeasons = req.body.seasons as number[] | undefined;
-
-        if (!requestedSeasons || requestedSeasons.length === 0) {
-          throw new Error(
-            'Missing seasons. If you want to cancel a series request, use the DELETE method.'
-          );
+        if (!request) {
+          return next({ status: 404, message: 'Request not found.' });
         }
 
-        // Get existing media so we can work with all the requests
-        const media = await mediaRepository.findOneOrFail({
-          where: { tmdbId: request.media.tmdbId, mediaType: MediaType.TV },
-          relations: { requests: true },
-        });
+        if (
+          (request.requestedBy.id !== req.user?.id ||
+            (req.body.mediaType !== 'tv' &&
+              !req.user?.hasPermission(Permission.REQUEST_ADVANCED))) &&
+          !req.user?.hasPermission(Permission.MANAGE_REQUESTS)
+        ) {
+          return next({
+            status: 403,
+            message: 'You do not have permission to modify this request.',
+          });
+        }
 
-        // Get all requested seasons that are not part of this request we are editing
-        const existingSeasons = media.requests
-          .filter(
-            (r) =>
-              r.is4k === request.is4k &&
-              r.id !== request.id &&
-              r.status !== MediaRequestStatus.DECLINED &&
-              r.status !== MediaRequestStatus.COMPLETED
-          )
-          .reduce((seasons, r) => {
-            const combinedSeasons = r.seasons.map(
-              (season) => season.seasonNumber
+        if (request.status !== MediaRequestStatus.PENDING) {
+          return next({
+            status: 409,
+            message: 'Only pending requests can be modified.',
+          });
+        }
+
+        const previousOwnerId = request.requestedBy.id;
+        let requestUser = request.requestedBy;
+
+        if (
+          req.body.userId &&
+          req.body.userId !== request.requestedBy.id &&
+          !req.user?.hasPermission([
+            Permission.MANAGE_USERS,
+            Permission.MANAGE_REQUESTS,
+          ])
+        ) {
+          return next({
+            status: 403,
+            message: 'You do not have permission to modify the request user.',
+          });
+        } else if (req.body.userId) {
+          requestUser = await userRepository.findOneOrFail({
+            where: { id: req.body.userId },
+          });
+        }
+
+        // Reassignment moves every season on the request onto the new owner's
+        // quota, so it is charged in full rather than as a delta
+        const ownerChanging = requestUser.id !== previousOwnerId;
+
+        return requestLock.dispatch(userKey(requestUser.id), async () => {
+          if (req.body.mediaType === MediaType.MOVIE) {
+            if (ownerChanging && !request.ignoreQuota) {
+              const quotas = await requestUser.getQuota();
+
+              if (quotas.movie.restricted) {
+                return next({
+                  status: 403,
+                  message: 'Movie Quota exceeded.',
+                });
+              }
+            }
+
+            request.serverId = req.body.serverId;
+            request.profileId = req.body.profileId;
+            request.rootFolder = req.body.rootFolder;
+            request.tags = req.body.tags;
+            request.requestedBy = requestUser as User;
+
+            await requestRepository.save(request);
+          } else if (req.body.mediaType === MediaType.TV) {
+            const mediaRepository = getRepository(Media);
+            request.serverId = req.body.serverId;
+            request.profileId = req.body.profileId;
+            request.rootFolder = req.body.rootFolder;
+            request.languageProfileId = req.body.languageProfileId;
+            request.tags = req.body.tags;
+            request.requestedBy = requestUser as User;
+
+            const requestedSeasons = req.body.seasons as number[] | undefined;
+
+            if (!requestedSeasons || requestedSeasons.length === 0) {
+              throw new Error(
+                'Missing seasons. If you want to cancel a series request, use the DELETE method.'
+              );
+            }
+
+            // Get existing media so we can work with all the requests
+            const media = await mediaRepository.findOneOrFail({
+              where: {
+                tmdbId: request.media.tmdbId,
+                mediaType: MediaType.TV,
+              },
+              relations: { requests: true },
+            });
+
+            // Get all requested seasons that are not part of this request we are editing
+            const existingSeasons = media.requests
+              .filter(
+                (r) =>
+                  r.is4k === request.is4k &&
+                  r.id !== request.id &&
+                  r.status !== MediaRequestStatus.DECLINED &&
+                  r.status !== MediaRequestStatus.COMPLETED
+              )
+              .reduce((seasons, r) => {
+                const combinedSeasons = r.seasons.map(
+                  (season) => season.seasonNumber
+                );
+
+                return [...seasons, ...combinedSeasons];
+              }, [] as number[]);
+
+            const filteredSeasons = requestedSeasons.filter(
+              (rs) => !existingSeasons.includes(rs)
             );
 
-            return [...seasons, ...combinedSeasons];
-          }, [] as number[]);
+            if (filteredSeasons.length === 0) {
+              return next({
+                status: 202,
+                message: 'No seasons available to request',
+              });
+            }
 
-        const filteredSeasons = requestedSeasons.filter(
-          (rs) => !existingSeasons.includes(rs)
-        );
+            const newSeasons = filteredSeasons.filter(
+              (sn) => !request.seasons.map((s) => s.seasonNumber).includes(sn)
+            );
 
-        if (filteredSeasons.length === 0) {
-          return next({
-            status: 202,
-            message: 'No seasons available to request',
-          });
-        }
+            if (!request.ignoreQuota) {
+              const quotas = await requestUser.getQuota();
 
-        const newSeasons = filteredSeasons.filter(
-          (sn) => !request.seasons.map((s) => s.seasonNumber).includes(sn)
-        );
+              // Only the seasons getQuota already counted for this owner are
+              // paid for, so the edit is charged for everything it left out
+              const quotaWindowStart = new Date();
+              if (quotas.tv.days) {
+                quotaWindowStart.setDate(
+                  quotaWindowStart.getDate() - quotas.tv.days
+                );
+              }
 
-        request.seasons = request.seasons.filter((rs) =>
-          filteredSeasons.includes(rs.seasonNumber)
-        );
+              const countedAlready =
+                !ownerChanging &&
+                (!quotas.tv.days || request.createdAt > quotaWindowStart);
 
-        if (newSeasons.length > 0) {
-          logger.debug('Adding new seasons to request', {
-            label: 'Media Request',
-            newSeasons,
-          });
-          request.seasons.push(
-            ...newSeasons.map(
-              (ns) =>
-                new SeasonRequest({
-                  seasonNumber: ns,
-                  status: MediaRequestStatus.PENDING,
-                })
-            )
-          );
-        }
+              const priorSeasonCount = countedAlready
+                ? request.seasons.length
+                : 0;
+              const requiredSeasons = filteredSeasons.length - priorSeasonCount;
 
-        await requestRepository.save(request);
-      }
+              if (
+                quotas.tv.limit &&
+                requiredSeasons > (quotas.tv.remaining ?? 0)
+              ) {
+                return next({
+                  status: 403,
+                  message: 'Series Quota exceeded.',
+                });
+              }
+            }
 
-      return res.status(200).json(request);
+            request.seasons = request.seasons.filter((rs) =>
+              filteredSeasons.includes(rs.seasonNumber)
+            );
+
+            if (newSeasons.length > 0) {
+              logger.debug('Adding new seasons to request', {
+                label: 'Media Request',
+                newSeasons,
+              });
+              request.seasons.push(
+                ...newSeasons.map(
+                  (ns) =>
+                    new SeasonRequest({
+                      seasonNumber: ns,
+                      status: MediaRequestStatus.PENDING,
+                    })
+                )
+              );
+            }
+
+            await requestRepository.save(request);
+          }
+
+          return res.status(200).json(request);
+        });
+      });
     } catch (e) {
       next({ status: 500, message: e.message });
     }
@@ -607,27 +665,30 @@ requestRoutes.put<{ requestId: string }>(
 
 requestRoutes.delete('/:requestId', async (req, res, next) => {
   const requestRepository = getRepository(MediaRequest);
+  const requestId = Number(req.params.requestId);
 
   try {
-    const request = await requestRepository.findOneOrFail({
-      where: { id: Number(req.params.requestId) },
-      relations: { requestedBy: true, modifiedBy: true },
-    });
-
-    if (
-      !req.user?.hasPermission(Permission.MANAGE_REQUESTS) &&
-      (request.requestedBy.id !== req.user?.id ||
-        request.status !== MediaRequestStatus.PENDING)
-    ) {
-      return next({
-        status: 401,
-        message: 'You do not have permission to delete this request.',
+    return await requestLock.dispatch(requestKey(requestId), async () => {
+      const request = await requestRepository.findOneOrFail({
+        where: { id: requestId },
+        relations: { requestedBy: true, modifiedBy: true },
       });
-    }
 
-    await requestRepository.remove(request);
+      if (
+        !req.user?.hasPermission(Permission.MANAGE_REQUESTS) &&
+        (request.requestedBy.id !== req.user?.id ||
+          request.status !== MediaRequestStatus.PENDING)
+      ) {
+        return next({
+          status: 401,
+          message: 'You do not have permission to delete this request.',
+        });
+      }
 
-    return res.status(204).send();
+      await requestRepository.remove(request);
+
+      return res.status(204).send();
+    });
   } catch (e) {
     logger.error('Something went wrong deleting a request.', {
       label: 'API',
@@ -644,26 +705,29 @@ requestRoutes.post<{
   isAuthenticated(Permission.MANAGE_REQUESTS),
   async (req, res, next) => {
     const requestRepository = getRepository(MediaRequest);
+    const requestId = Number(req.params.requestId);
 
     try {
-      const request = await requestRepository.findOneOrFail({
-        where: { id: Number(req.params.requestId) },
-        relations: { requestedBy: true, modifiedBy: true },
-      });
-
-      if (request.status !== MediaRequestStatus.FAILED) {
-        return next({
-          status: 409,
-          message: 'Only failed requests can be retried.',
+      return await requestLock.dispatch(requestKey(requestId), async () => {
+        const request = await requestRepository.findOneOrFail({
+          where: { id: requestId },
+          relations: { requestedBy: true, modifiedBy: true },
         });
-      }
 
-      // this also triggers updating the parent media's status & sending to *arr
-      request.status = MediaRequestStatus.APPROVED;
-      request.modifiedBy = req.user;
-      await requestRepository.save(request);
+        if (request.status !== MediaRequestStatus.FAILED) {
+          return next({
+            status: 409,
+            message: 'Only failed requests can be retried.',
+          });
+        }
 
-      return res.status(200).json(request);
+        // this also triggers updating the parent media's status & sending to *arr
+        request.status = MediaRequestStatus.APPROVED;
+        request.modifiedBy = req.user;
+        await requestRepository.save(request);
+
+        return res.status(200).json(request);
+      });
     } catch (e) {
       logger.error('Error processing request retry', {
         label: 'Media Request',
@@ -682,41 +746,44 @@ requestRoutes.post<{
   isAuthenticated(Permission.MANAGE_REQUESTS),
   async (req, res, next) => {
     const requestRepository = getRepository(MediaRequest);
+    const requestId = Number(req.params.requestId);
 
     try {
-      const request = await requestRepository.findOneOrFail({
-        where: { id: Number(req.params.requestId) },
-        relations: { requestedBy: true, modifiedBy: true },
-      });
-
-      let newStatus: MediaRequestStatus;
-
-      switch (req.params.status) {
-        case 'approve':
-          newStatus = MediaRequestStatus.APPROVED;
-          break;
-        case 'decline':
-          newStatus = MediaRequestStatus.DECLINED;
-          break;
-        default:
-          return next({
-            status: 400,
-            message: 'Status must be approve or decline.',
-          });
-      }
-
-      if (request.status !== MediaRequestStatus.PENDING) {
-        return next({
-          status: 409,
-          message: 'Only pending requests can be approved or declined.',
+      return await requestLock.dispatch(requestKey(requestId), async () => {
+        const request = await requestRepository.findOneOrFail({
+          where: { id: requestId },
+          relations: { requestedBy: true, modifiedBy: true },
         });
-      }
 
-      request.status = newStatus;
-      request.modifiedBy = req.user;
-      await requestRepository.save(request);
+        let newStatus: MediaRequestStatus;
 
-      return res.status(200).json(request);
+        switch (req.params.status) {
+          case 'approve':
+            newStatus = MediaRequestStatus.APPROVED;
+            break;
+          case 'decline':
+            newStatus = MediaRequestStatus.DECLINED;
+            break;
+          default:
+            return next({
+              status: 400,
+              message: 'Status must be approve or decline.',
+            });
+        }
+
+        if (request.status !== MediaRequestStatus.PENDING) {
+          return next({
+            status: 409,
+            message: 'Only pending requests can be approved or declined.',
+          });
+        }
+
+        request.status = newStatus;
+        request.modifiedBy = req.user;
+        await requestRepository.save(request);
+
+        return res.status(200).json(request);
+      });
     } catch (e) {
       logger.error('Error processing request update', {
         label: 'Media Request',
diff --git a/server/utils/requestLock.ts b/server/utils/requestLock.ts
index ca980ad47..79d3d9156 100644
--- a/server/utils/requestLock.ts
+++ b/server/utils/requestLock.ts
@@ -1,7 +1,10 @@
 import AsyncLock from '@server/utils/asyncLock';
 
-// Keyed on user id. Never dispatch from a subscriber or transaction as a waiter
-// would block while holding the save's connection.
+// Keyed on user id or request id. Never dispatch from a subscriber or
+// transaction as a waiter would block while holding the save's connection.
 const requestLock = new AsyncLock();
 
+export const userKey = (userId: number) => `user:${userId}`;
+export const requestKey = (requestId: number) => `request:${requestId}`;
+
 export default requestLock;