Generally between 7-9. I don't like getting less than 8, but my body usually puts me in for a good 7 hours at least if I sleep in (get home at 3 am, wake up at 10). During the week I always do a lot of physical activity so I'm exhausted enough by 10pm before I have to wake up at 6 (8 hours) but I may go to sleep earlier for that lovely 9 .
7 on average whilst attending school, if i sleep through my alarm i can sleep for aggggggges. :< slept for 15 and a half hours the other day, night before that 12.