We do conditioning at the gym for around an hour to 40 minutes.. But we also do conditioning during events. Yes I do conditioning at home. My coach gave us a Geddart's Twistars conditioning sheet which is very helpful in conditioning at home. And lastly, no we do not HAVE to do conditioning during breaks and at home, but I mean gymnastics basically revolves around strength and flexibility, so lets be real here, if you aren't doing any conditioning, it is going to be a struggle for you to do gymnastics well. Just my opinion.
We spend 30 minutes of practice conditioning. Lately I have been doing a lot of conditioning due to an injury, at least 2 hours of pure conditioning. If I feel like I am lacking in a certain area (wrist strength, glutes, arms/abs) I will do a set of pt exercises, L-leglifts, etc. Sometimes I will try to challenge myself by doing a sprint workout or completing a hard conditioning list. Over breaks I won't do anything major as I am busy with other things.