Coroutines and Time.timeScale

           Most important thing need to keep in mind while using Coroutine is that, Coroutine is affected by Timescale.
           
           When time scale is reduces to 0 then Coroutine won't be called. This is the different behavior then MonoBehaviour Update() call which is still getting invoked even after Timescale reduced to 0.

More notes about Time.timeScale,

• Factors affected and not affected by Time.timeScale

• Time.timeScale and iTween ignoretimescale property

Best Practice for Game Development!