In my house the >8 years old the kids start paying rent. They get paid for normal house work (minimum wage). Rent is ~$300/month. I pay the kid minimum wage for chores because that is work and work should be rewarded. They pay me rent. That rent and other expenses are ~80% of their pay. Some must go to savings and "taxes". They have to keep books as well. The rest is theirs.
I know other fathers that charge their adult children rent, keep the money, and then gift it to them at the wedding or to help them buy a house.
I know other fathers that charge their adult children rent, keep the money, and then gift it to them at the wedding or to help them buy a house.