When does the day end?

Here's a blurb from The Gospel Coalition's paper entitled "Human Flourishing":

Another change brought about by technology is that students now submit assignments electronically. This frees professors to set deadlines for assignments at midnight or 6 am. When I was a college student, students had to physically hand in papers that were due during the day or by 5 pm, the time when the departmental office closed. As a result, this drew a clear boundary between the school day and the evening. Now professors contribute to a “work around the clock” way of life by having middle-of-the-night or weekend deadlines, thereby encouraging students to work at all times. Because work can be accomplished anywhere at any time, students feel pressure to always be working. There is a blurred distinction between day and night, and sleep schedules are often erratic.

I'm trying to get back to "normal" hours, but last night I didn't get a whole lot of sleep. It wasn't so much due to a midnight or 6am deadline - more a matter of just not being able to fall asleep - but it may be an end result of a schedule that's tended to incorporate too many odd hours.

This whole sleeping at appropriate times thing seems to require that self-discipline be improved - either that or life in community - the presence of other individual(s).