When you have a Rails app that depends on Sidekiq (and Redis) for processing background jobs, it is critical to monitor queue latency to make sure there are enough Sidekiq workers running based on the volume of jobs at any given time. In Sidekiq, queue latency is the difference between when the oldest job was enqueued and the current time. To take full advantage of distributed job processing, the latency of each job queue must remain very low.