My son is 3 years old and lately he has been having problems sleeping. I've heard kids his age are supposed to sleep around 10-12 hours a day, although I'm no sure. He used to sleep on the afternoons but now he refuses to.
He only sleeps at night, we put him to bed around 9 PM but he always tries to slip from his room. After a couple of times of returning him to bed he finally falls asleep around 10, 10:30, sometimes even 11PM but he usually wakes up several times at night. At 7AM he is already up and playing with his toys.
I used to think it was just he growing up but we have noticed that he gets cranky and sometimes a little violent (he gave a another child quite a bite the other day) and we think it might be related with his sleeping disorder.