comfort zone 
noun
1A situation where one feels safe or at ease: the trip is an attempt to take the students out of their comfort zone...
- Finally, my journey has taken me well and truly out of my comfort zone and into unknown territory.
- It's a continuing comfort zone of zero change in an ever changing world.
- As we have said before here, his job is safe; he is operating in the same comfort zone as his players.
1.1A settled method of working that requires little effort and yields only barely acceptable results: if you stay within your comfort zone you will never improve...
- It feels like there aren't any great options that are within the comfort zone for both of us.
- You encourage us to go beyond our comfort zone, to take the risk of change for the better, because we are worth it.
- Reaching beyond the comfort zone can take a lot of coaxing and frustration.