Having 3 kids, I put them to sleep by 9.30. There's a loop that they can't fall asleep when they're tired and they're tired because they don't get enough sleep, so we even make sure they have excess sleep if possible. Otherwise they get cranky and it's a bad day/week/month for everyone.

I realise I could just wake up earlier to do stuff, and if I wake up early, I'm also less likely to waste it on pointless things.