When do your sims children usually move out of their parents house? In my case, it's usually as a teenager, because I am unable to properly focus on the storylines of more than 1-2 sims at the time...
I agree with you, I usually switch my focus over to the teens once they become teens. I don't move them out though, unless there was some reason why they needed to. Instead I let the parents autopilot a bit more until the empty-nest stage after the teens grow up to YA and move out.