As much as I can. I'll go to bed when I'm tired which is usually 10:30/11pm, especially if I have Uni/Workshops the next day as I need to get up earlier to prep my food for the day.
I won't go to bed if I'm not in the mood for sleep as I just end up frustrated that I can't get to sleep and end up more tired the next day.
Usually a minimum of 7hours, average about 9, unless I'm trashed no more than 11. Don't like getting up in the afternoon or wasting the day. Normally up at half 7 at the earliest, 9 at the latest.