I have a gym membership and most days I go with my best friend in the daytime(he works nighttime) or my brother(he works daytime) in the nighttime. They both really enjoy exercising with me, having a spotter, someone to help fill bottles etc, so I go twice some days. Is it bad to go hard once and then take it easy and focus on time under duress for my second visit? Is one trip all I should be taking a day? If I do go twice should I change up my workouts?