Dd lived at home for 2 years after leaving college; ds has just left college and will be living at home for the foreseeable future.
Financial contribution once they are earning.
Required to shop and cook one family meal a week. Once you have committed to that day, you simply can't change your plans (at least not without negotiation), any more than a parent can suddenly decide not to cook for the family.
As I often work late anyway, those around for a meal eat together when food is ready and whoever comes in late can heat up the leftovers. Whatever is left the next day can be eaten for lunch by whoever wants it.
Expectation to let family know if you will not be home in the evening, and particularly if you will be staying out all night (I don't want to wake up at 3 in the morning and have to wonder if that is my son or a burglar).
NO expectation to tell us where he is going. Really none of my business- though of course it is nice when he comes and talks about his life.
General usefulness around the house on an ad hoc basis.
Laundry we tend to do as family loads, and whoever finds they are running out of clothes first puts a load on, but fills machine up with other people's clothes once their own are in.
I do like having him around. I miss dd, though in her case it was more worrying that she was still at home, as she had health problems which I feared would make it harder for her to move away.