I would say I average 45 min per muscle group, two muscle groups (workouts) a day. Today from 530am to 615am was quads and 630pm to 715pm was back. This system works great for me. Athough, I'm limited by my gym opening at 530am and having to be at work from 700am to 600pm.
I do think I may have overtrained in my last deca cycle. I was getting great gains up until week 8 or 9 and then I just plateau'd for the rest of the cycle, but I was really getting after it spending 2.1/2 to 3.1/2 hrs a day in the gym busting my ass every second. I can't say that I was sleeping well during that cycle either.