Comment by galvarez800

This makes perfect sense to me. From what I've seen anecdotally, it seems most people can work 80-hour weeks at full productivity for maybe one or two weeks, tops. After that, the fatigue starts to set in and that person's performance starts to decline. In the long run, the person working 80 hour weeks isn't getting much more done than someone working far fewer hours, simply because during those 80 hours they are operating at greatly diminished mental capacity.