Kids should be in bed at 8:00. No exceptions.

I believe the OP is joking but tend to agree that it seems many parents are too lenient. Why should a 3-6 year old go to bed at 10? Whats the rationale behind it? 8 it is. It doesnt mean they have to fall asleep right away. Play with a toy read a book, whatever, just stay in bed and go to sleep by 9 or so.

7-13 i would say 9 and go to sleep by 10.

14-16 - 10 to sleep by 11.

17 and onwards, all hope is lost; just please come home on most nights