Ds5.5 most days until about 4, occasionally until about 4.5. Until he was about four he could sleep 3 hours until 4 then go back to bed at 6.30 then sleep until 5.30 to 6.30 the next morning. He still is often asleep by 7 and sleeps 11 to 12 hours a day. I don't remember when he dropped his morning sleep. Ds3.5 dropped his morning sleep about one and his other mostly by 2. On the rare occasion he slept he would be awake until 10.30 or 11. He is quite happy on 10 hours sleep.