>I read till I go over the same section again and again, then realise I haven't taken it in. Then I put down the book and drop off immediately. Otherwise I'm a life-long semi-insomniac. I'm more or less indefatiguable.

Some people like my sister in-law need 5-6 hours sleep. My wife, if she can get it will sleep for 10 hours. When I was a teenager I could sleep for 12-14 hours.