My sleep habits completely changed some time between age 50 and 60. Nowadays I couldn't sleep a solid 8 hours straight through unless you filled me full of downers and stuck me in an isolation tank...and then I'd still probably wind up pissing myself.

fwiw my sleep habits also completely changed some time between age 20 and 40, but that was more about how long it took me to fall asleep. Seems like there was really only a relatively narrow window of my life when I could fall asleep shortly after getting into bed and stay asleep until an appropriately full night of rest was achieved.


[edit: Naps are great! We need more officially-endorsed siesta time in this country!]