I meet a fair number of parents whose kids don’t fall asleep as fast, or stay asleep as long as they’d like. There can be many reasons for this, but a surprisingly common one is that the parents expect their child to sleep longer than he or she is able to.
If your 3-year-old is getting a two-and-a-half hour nap at daycare, it’s not reasonable to expect that he’ll fall asleep at 7 PM and stay asleep until 7 AM. Most 3 year olds need about 11 hours of sleep in total during a 24-hour period, and if they’re getting a lot of daytime sleep, it’s going to come at the expense of nighttime sleep.
As I explain to parents, if someone were to lock them into a bedroom for 16 hours, they might sleep 8, 9, or even 10 hours (if they were really sleep deprived, which many are!), but at some point, they’d wake up and start looking for something else to do: read a book, watch TV, etc. The need for sleep is, after all, driven by the brain, and it is very difficult if not impossible to simply will yourself to sleep when that need simply isn’t there.
Many parents have trouble reconciling this with what they hear from other parents, who report that their child get a solid 12 hours of sleep at night even after taking a two-hour nap in the afternoon. Why can’t my child sleep like theirs? they ask.