My rules on overnights were the same for friends or lovers: only people I’d met before. I had no desire to encounter strangers on a nighttime loo dash, or at breakfast!
Mine had chores and responsibilities from when they were young, and once they were adults and working, I considered they should be, in practical terms, doing as much as me, since I also worked full-time.
They contributed towards the household costs (proportionately less than me, they had no equity in my house), were expected to share routine housework, cooking, and gardening (until one of them dug up all my precious white violets), They weren’t permitted to smoke or do drugs in the house, and they were expected to be polite to me no matter how fed up they were with me.
I did not, obviously, have curfews or restrictions on how they spent time away from the house, how they dressed, had their hair cut, or spent their money (I tried to encourage some saving, semi-successfully) because they were adults, and anyway young people should do somewhat daft or outrageous things now and then. .