The honest answer is I dont xD I work full time and I have a partner and parents who are always in need of a hand so I basically have to squeeze whatever I can do into 5-6 hours on weekday evenings (Monday to thursday) if for whatever reason I get a weekend free (Very rare but it does happen) I usually try and schedule in some additional videos or I catch up on TV/video games that I've been meaning to get on with...but the reality is my youtube life and my actual life have pretty much blurred together xD
To be perfectly honest, how do I balance YouTube with my life? I don't! That might sound strange, but at the moment I've been on fire with video ideas, and despite having a thousand and one other things to do in my life, I've dedicated myself to making YouTube something that pays the bills. Sure - I still go out and spend time with friends and family, and I do do other things around the house too, but YouTube right now is my main focus.

I suppose there is a line, though. If you're in a situation where YouTube literally gets ion the way of your normal day-to-day life, then it's time to do something about that, but for me, I think I can manage a pretty even keel between YouTube and Life in general overall despite my above statement. I have my health, my fiance and my son to worry about as well so I guess that sort of forces me to balance things properly.