To never ever let kids stay up seems nutty and unrealistic, but the research is pretty clear — and it doesn't take a longitudinal study to tell you kids behave better if they get regular sleep. It's pretty apparent the next day.
Some kids are obviously easier than others to deal with, but doing everything you can to impose total victory early seems way easier in the long run than having new battles every night, like some people seem to do. But depends on personalities, work schedules, etc.
Seems weird to never let them stay up late though — on vacation, for gatherings, etc.
Apparently it's not just how much they get on average, but the regular bedtime makes a huge difference: