i am guessing you are asking this because he/she won't go to bed. ten hours would be great for these little people but you may have to work up to that ideal time. four year olds have a hard time turning off those active brains of theirs so you need to develop a good nightime ritual. turn of the tv and no computer games one hour or so before bedtime. give him a quiet soothing bath find a good book with mutiple chapters and read to him while he is snuggled and cozy in his bed. the book should provoke sweet dreams so choose wisely get a "white sound" machine; the type that plays babbling brooks bird noises etc. a radio with some soft soothing music works too. no caffeine or anything known to stimulate him before bedtime. this includes rough-housing. keep the house boring for at least an hour a glass of warm milk (no chocolate! ) can be part of the ritual. i tell boys that they only build musles when the sleep or girls only get prettier when they sleep. last resort? pay them to stay in bed. i prefer this method: give them ten dollars worth of quarters that is his or hers to keep at the end of the week. however if they want to stay up later it will cost 50 cents. if they get up and say "i can't sleep". 50 cents. if they leavs their room for any reason other than the bathroom. 50 cents. they will soon learn the value of money and the cost of not going to bed. this is fun. try it. it works.
how much sleep should my 4 yr old be getting a night?