Last semester I had class really early in the morning two days a week and another two days a week my first class was in the afternoon. This made it really hard to have a regular sleeping schedule and so what I would do is stay up until 3 or 4 every night.
but this semester i made sure my schedule was more regular than that. now i have class at 10 so i can stay up a little bit and still get a fair amount of sleep, or i can go to sleep early without feeling ridiculous.
i feel a lot healthier because of it.