Somebody besides me mentioned erratic sleeping habits. I meant to post this there but couldn't find it back. Drat! In any event, I once took a year off to see if I could write for a living (answer was No!) and developed some erratic sleeping habits.
I tended never to sleep more than about four hours at the longest and would often go for an entire twenty-four hour period without sleeping more than one hour at a time. Overall I think I averaged between six and seven hours sleep every day with a four-hour stretch somewhere in every thirty-six or so. It was actually quite pleasant.
I have since read that patterns similar to this short naps and a longer one intermittently tends to be the rule with those who have no other schedule imposed on them and who are not governed by the sun.
! I think I feel a story coming on here. . . what if the world didn't have business hours from 9-5, but just operated whenever you were awake?