Without sleep, there are too many hours in the day. Sometimes, you do have things to do, but do you really want to code 24/7? Besides, from my experience, I am very lethargic and crabby if I do not get 7-10 hours of sleep. If I've been going on 4-5 hours of sleep all week, I'll usually "catch up" on the weekend, sleeping for up to 12 hours or more rarely 14 hours.