Fully depends on the set up.
Cousins 35yo DS lives with her, separated from his wife, has a young child. My cousin can no longer work due to medical reasons, they get on really well, have always been close. Him contributing helps her, she gets time with her grandchild and has a loud house which she’s loves. Her adult DD has also lived with her in the past.
My adult niece, 26 lives with her parents, again they are close, always spend a lot of time as a family together. Her and her DM go on holidays with my other niece and shopping weekends together, they all work together (family business) so it’s convenient transport wise. She regularly stays with her DP but no desire to move out, it works for them. Her sister moved out when she went to uni and although works for the family business choose not to move back home because that worked for her.
I left home at 18, went back briefly twice, 20 & 23 absolutely hated it but needed to at the time. I couldn’t think of anything worse than living with my parents, particularly my toxic M. Had I had the relationship my cousin and brother have with their children then I may well have stayed home longer.