Newbie Landlord in San Diego

Hi Bigger pockets, I'm a new landlord in San Diego, about to deal with my first turnover in tenants.  My tenant asked me if they gave notice on the 15th of the month, could they move out then, or must the notice be given on the 30th/1st of the month.  Am I allowed to require that notice must be given at the beginning of a month?  Do I even want that?  Or are there advantages to having them move out on 15th?  Please help!  Thank you!