I try to get 8-9 but usually get 5-6, and very, very rarely more than 7. Back when I was still at home, I didn't get off work until 9, and then still had to get in my lifting and homework after that. Now, I get done in the training room around 7-8, still have to train, and never can manage to get in bed before midnight (usually later). Then I get up for 8 am classes.
Somewhere a while back, I read that people who get 5-6 hours of sleep per night live quite a bit longer than people who get a "full 8." Whoever did the study wasn't able to identify the mechanism(s) that caused that, but it was a pretty wide ranging study.