[throwamon]

Whether or not you're right, you just reinforced my point of there being some (maybe semi-conscious) scorekeeping happening, and the point on there maybe being some underlying issue (psychological or even social - we know young adults living with their parents is becoming a trend and I'm sure in many cases there's much more to it than simply "being coddled as if they're still children").

[TeMPOraL]

It's not score keeping. It's recognition that we don't live in a post-scarcity society, and our needs don't satisfy themselves. Labor and money are still required to keep quality of life in a household at a stable level.

I don't think turning 18 is the common boundary line here. Entering the workforce is. If you're making money while still consuming your parents' household resources, it's only reasonable to contribute something back. FWIW, I'd hope most people who generate income while living with their parents would recognize this as obvious, and volunteer to pay rent.