I think 15-20 hours of work a week is natural. That is the amount the Kung Bushmen have been known to work per week gathering food. The rest of the time is le

I think 15-20 hours of work a week is natural. That is the amount the Kung Bushmen have been known to work per week gathering food. The rest of the time is leisure. When at work, I use a timer to time the time spent in actual productive programming. I find that if I start to go over 20 hours of productive work a week, I start to become miserable and my body reacts by bringing on colds or allergies. Perhaps your friend chooses to work at a grocery store because he can't find a job in his field where he would have the opportunity to only work 15 hours.