When it's ok

Usually, adult children should not return home after going away to university. Once you can pay your own way, all adult children should live on their own so as to learn how to be responsible, unless they have parents who need their help and finances. Then, any time the person decides they've done all they can for their family.

I think it really depends on the situation. Children with mental, emotional, or physical disabilities obviously often need to remain at home longer than other children. Also, some people are just late starters, and benefit from a little more time to learn who they are and what they want to do before being on their own. In general, I think most kids are ready to get out of the house when they finish school, but others might need a few more years of help before they are ready to be on their own. Even a child living at home, however, as an adult should have certain responsibilities. I don't believe in letting your children sponge off you (unless they are disabled in some way or have some kind of emergency that requires help). I would prefer that my child move out by the time he is 21 at the latest. Actually, I would hope he wishes to do so before that, but I think that's the latest I would let him live at home without some kind of extenuating circumstance making it necessary. I have seen what being allowed to be irresponsible can do to people (my own father lived in my grandmother's basement most of the time until he was 40). I, on the other hand, was forced to move out at 18, while I was deathly ill, which I would never do to a child.

Whenever the family is ok with it. If the child wants to move out as soon as they are legal age...then ok...if they want to stay longer and the parents are ok with it, then that is good too. Everyone and every family is different, it is all about what works best for that family!