It would take a very long post to explain mine lol :| my working hours vary a lot and my natural sleeping pattern if left to my own devices is quite offset from normal and there is nothing I can do to change that (which means on an early start I barely get any sleep and on a late start I sleep off quite a bit of sleep debt). If I have no alarm set and a week off work I will reset to sleeping ~3am to just gone 11am getting just over 8 hours of sleep and waking naturally feeling refreshed and ready to go - this rarely happens normally tho - anything less than 6 hours I'm barely functional.
This week was something like:
mon: 10 hours sleep, no work
tues: 3 hours sleep, 6 hours work
wed: 5.5 hours sleep, 10 hours work
thurs: 3 hours sleep, 7 hours work, 3 hours sleep (came home and went to bed again).
fri: 4 hours sleep, 6.5 hours work
sat: 8 hours sleep, 4.5 hours work