[jusben1369]

One of the fascinating parts about needing "x hours of sleep per night" and in the past people slept "x hours a night" is I never see anyone take into account the seasons. For all of us at one end of the year we're in a place with 14 hours of darkness and later we're at 14 hours or more of light. I think that impacts how much sleep we need probably by 10 - 20%. I for one hate 6:30am flights in winter when it's dark but don't find them nearly as hard in the middle of summer when the sun's been up for an hour.