My sleep habits changed when I hit 50. I sleep 3-4 hours, am up an hour or two and then go back to sleep for 2-3 hours. On average I get 6 hours of sleep per day. I do OK with it, but think I'd be sharper if I got 7 or 8 solid hours without interruption every night. My brother, Jon, sleeps the same pattern as mine. Weird. Maybe its in the genes.