Mostly I want them to leave the house before they break mommy when they reach adulthood. I’ll be polite about it, but once they reach 20 I will strongly suggest that they leave. We hope to teach them self-sufficiency before that age.
We are lucky enough to have in-laws who love horses and have access to their farm. There are 2 ponies (soon to be 3) and a horse in residence at the moment. The girls are learning to ride, but even more importantly, they are learning to work and care for creatures. Twice a day they are over at the barn putting them in and out (in the winter, anyway) and feeding them. They grumble a bit about cleaning the stalls and grooming the ponies, but they love them and in the end are willing to put in the work. It’s been a great starting point to teaching them that it takes all members of the household to keep it running.
And it gives me no small amount of pleasure to see them shoveling horse manure.