A company I worked for would say: There are 3, 8 hour shifts a day. 1 belongs to the company, 1 belongs to sleep, and the 3rd one is your time. Say you get off at 4 am and home in bed by 5 am. 8 hours sleep gets you up at 1:00. If you have to leave at 7:00 to get to work, you have from 1:00...