That different cities have different codes regarding rentals?
For instance, the Seattle Municipal Code* includes requirements that there be deadbolts on entry doors, dead bolts or other approved locking devices on all sliding patio doors, that locks be re-keyed between tenants and the prohibition against double cylinder deadbolts. It also specifies the type of locks required on garage doors and on opening windows.
In order to reduce liability to the owner, it is a good idea to re-key locks between tenants even in municipalities that don’t require this action.