I think if the parents can afford mortgage, utilities, groceries, etc. they should not charge the child for any of that regardless of whether or not the child is working. Obviously, if they are struggling financially (such as in Asian families especially in the older generation, the parents don't have much and are entirely dependent on their children), that is a different story. They are already paying mortgage and utilities to begin with, and increased groceries should not cost much more if the family is all eating the same food (rather than different meals). Obviously, the child should pay for his/her own stuff (clothes, hobbies, medical), and should be generous in other ways such as paying for eating out, outings, etc. Along the same though, an adult child should not be charging an elderly parent rent, groceries if the parent is staying in the child's home. I don't know, charging a child or parent rent, unless there are some financial issues, seems not the thing to do in a family.