diff --git a/app/workers/scheduler/backup_cleanup_scheduler.rb b/app/workers/scheduler/backup_cleanup_scheduler.rb
index 5ab16c057..cfdf6f4af 100644
--- a/app/workers/scheduler/backup_cleanup_scheduler.rb
+++ b/app/workers/scheduler/backup_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::BackupCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     old_backups.find_each(&:destroy!)
   end
diff --git a/app/workers/scheduler/doorkeeper_cleanup_scheduler.rb b/app/workers/scheduler/doorkeeper_cleanup_scheduler.rb
index bab4ae886..fec08c6bc 100644
--- a/app/workers/scheduler/doorkeeper_cleanup_scheduler.rb
+++ b/app/workers/scheduler/doorkeeper_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::DoorkeeperCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     Doorkeeper::AccessToken.where('revoked_at IS NOT NULL').where('revoked_at < NOW()').delete_all
     Doorkeeper::AccessGrant.where('revoked_at IS NOT NULL').where('revoked_at < NOW()').delete_all
diff --git a/app/workers/scheduler/email_scheduler.rb b/app/workers/scheduler/email_scheduler.rb
index 36866061b..1a5a1c826 100644
--- a/app/workers/scheduler/email_scheduler.rb
+++ b/app/workers/scheduler/email_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::EmailScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     eligible_users.find_each do |user|
       next unless user.allows_digest_emails?
diff --git a/app/workers/scheduler/feed_cleanup_scheduler.rb b/app/workers/scheduler/feed_cleanup_scheduler.rb
index 42cf14128..b02bac883 100644
--- a/app/workers/scheduler/feed_cleanup_scheduler.rb
+++ b/app/workers/scheduler/feed_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::FeedCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     clean_home_feeds!
     clean_list_feeds!
diff --git a/app/workers/scheduler/ip_cleanup_scheduler.rb b/app/workers/scheduler/ip_cleanup_scheduler.rb
index 613a5e336..6bb93df7d 100644
--- a/app/workers/scheduler/ip_cleanup_scheduler.rb
+++ b/app/workers/scheduler/ip_cleanup_scheduler.rb
@@ -5,6 +5,8 @@ class Scheduler::IpCleanupScheduler
 
   RETENTION_PERIOD = 1.year
 
+  sidekiq_options unique: :until_executed
+
   def perform
     time_ago = RETENTION_PERIOD.ago
     SessionActivation.where('updated_at < ?', time_ago).destroy_all
diff --git a/app/workers/scheduler/media_cleanup_scheduler.rb b/app/workers/scheduler/media_cleanup_scheduler.rb
index c35686fcb..a27e02953 100644
--- a/app/workers/scheduler/media_cleanup_scheduler.rb
+++ b/app/workers/scheduler/media_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::MediaCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     unattached_media.find_each(&:destroy)
   end
diff --git a/app/workers/scheduler/subscriptions_cleanup_scheduler.rb b/app/workers/scheduler/subscriptions_cleanup_scheduler.rb
index af2ae3120..06ba66205 100644
--- a/app/workers/scheduler/subscriptions_cleanup_scheduler.rb
+++ b/app/workers/scheduler/subscriptions_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::SubscriptionsCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     Subscription.expired.in_batches.delete_all
   end
diff --git a/app/workers/scheduler/subscriptions_scheduler.rb b/app/workers/scheduler/subscriptions_scheduler.rb
index dc16e85c2..4b0959af2 100644
--- a/app/workers/scheduler/subscriptions_scheduler.rb
+++ b/app/workers/scheduler/subscriptions_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::SubscriptionsScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     Pubsubhubbub::SubscribeWorker.push_bulk(expiring_accounts.pluck(:id))
   end
diff --git a/app/workers/scheduler/user_cleanup_scheduler.rb b/app/workers/scheduler/user_cleanup_scheduler.rb
index 245536cea..dde195bff 100644
--- a/app/workers/scheduler/user_cleanup_scheduler.rb
+++ b/app/workers/scheduler/user_cleanup_scheduler.rb
@@ -3,6 +3,8 @@
 class Scheduler::UserCleanupScheduler
   include Sidekiq::Worker
 
+  sidekiq_options unique: :until_executed
+
   def perform
     User.where('confirmed_at is NULL AND confirmation_sent_at <= ?', 2.days.ago).find_in_batches do |batch|
       Account.where(id: batch.map(&:account_id)).delete_all