On the other hand, I want the least amount of money to leave the "clan" as possible, paying rent gives money to another "clan."
More and more extended families are going to have to take this approach.
Funny you should raise that point as I am more and more beginning to assume that view. My kids are not that old and they are just beginning to work. I have actually been framing things in much that same way.
The kids are healthy and will move out at the appropriate time, but strengthening the clan financially ultimately helps them long after Mr. and Mrs. Obadiah are gone.