It depends a lot on the situation. My exparents lived with my paternal exgrandparents until I was 8. Completely seperate households tho. Just in the same house.
If theres a partner and kids it’s important that everyone negotiates boundaries and communicates well. If it’s one household the chores and finances need to be shared in a way that works and so on.
Personally I moved out as early as I could because these people are abusive. I find it awe inspiring that you manage to coexist peacefully when everyone is an adult. If it works for you it works for you. In many cultures living with your parents is normal. I think worrying about what other people think, those that won’t pay your rent and don’t interact with your family isn’t productive. You’re the one who has to live with the decisions you make.