Legal Question in Real Estate Law in California

Re: Apartment guest

I do not know of any bright-line test for when a guest becomes a subtenant. It's usually case by case based on the facts and circumstances.

A guest probably loses that status when he/she moves in furniture, has no other home, receives mail, contributes to maintenance or expenses, buys own food, etc.

You might look at a tenants' rights book at your library or buy one for more detail.