When did your child(ren) live away from home --if childfree, nieces, nephews

Inspired by many responses for when you first left home to live away from parents https://www.reddit.com/r/AskWomenOver60/comments/1sdi4cw/comment/ofafjh3/

Time moves on. When did you your child(ren) live away from home? What do you think is ideal age/time?