I work at a factory that swings shifts every six weeks. So, my sleep depends on my shift.
If I am working day shift, I get off at 7:00 pm, I go to bed at 9:00 pm and wake up at 5:00 am.
If I am working night shift, I get off at 7:00 am, go to bed at 10:00 and wake up at 5:00 pm.