About 4 hours a night for me. Been like that for as long as I can remember...even when I was a kid. My brother, Dad and Aunt are all the same way so maybe it's in the genes. Either way - 4 hours is enough to keep me charged throughout the day which includes work, an hour to and an hour and a half of exercise and chasing around a three year old. I've tried sleeping longer, but it just gives me a headache.