Usually 9 or 10 hours, sometimes a bit more. I'm one of those people who absolutely cannot function with less than 8 hours of sleep, at least not without some major naps taking place during the day. Even 8 or 9 hours will sometimes leave me experiencing bouts of sleepiness throughout the day. Quite frankly it sucks. I'm envious of my girlfriend who can often go about her day with 6 hours of sleep and experience no ill effects.