I'm on the body-for-life program doing all upper body (n lower in another session) in a session 6 sets with 12-10-8-6-12-12 reps (set 1,2,3,4,5,6) (1 min between sets last set no break, 2 min between muscle groups) with weight going up then down for my last two sets so my intensity should be (5,6,7,8,9,10) in correlation with my sets. However instead of sticking to it ive varied it a little including ab's which is normally lower body routine. Normally with upper body in a session ill crank out bi's, tri's shoulders, back, chest, abs. It takes me about hour-hour twenty, any longer i dont think is good for you what im told but im yet to get hard evidence behind it. I guess it depends on what your doin, strength, size, endurance, what you've eaten etc. Anyone elaborate on what 'how long is good time and bad time' in the gym with references or experiences?