Releasing changes from a sandbox into production Salesforce can be an interesting time as a developer.
As your instance gains more and more code, and tests, the amount of time it takes for changes to deploy increases.
Quick deploy is a relatively new feature that can deploy components up to 96 hours after they have been validated. This can be incredibly handy, if you are needing to deploy changes that may cause a temporary service interruption or invalidate a page’s viewstate.
My personal favourite use is starting the validation at the end of the day and then being able to deploy first thing.
Author: Brian Cline