I've been trying to get used to 5 to 8 hours of sleep, 6.5 hours per day on average for a month now. There are still some days where I just want to sleep in, and if I do sleep in I'll oversleep for 12 hours. Here is the thing, I can easily run on less than 7 hours of sleep, but when I wake up I always feel tired for the first 10 minutes upon waking, but that's probably normal. Then a few hours later, while sitting in class, I'll want to go for a nap, but it's easy to stay awake. When I get home from school I'll get the same sensation - again, it's easy to stay awake. So, how much longer until my body gets used to 6 to 8 hours of sleep, everyday? If I sleep in during the weekends, will this hamper my "adaptive progress"? Should I really try and wake up at the same time every day, regardless if I'll only sleep for 3 to 5 hours before waking? Other notes: In the last 2 years, I was used to sleeping in for longer hours; I stayed in bed anywhere from 9 to 12 hours. I sometimes forced myself back to sleep because it just feels so comfortable... my bed.