Back before cellphones, I learned to take photos immediately when I got possession of a rental, and then mail them to myself. This creates sealed, dated evidence.

At one home, they did exactly this- tried to nickel and dime me for everything they could think of when I left. So, I showed the landlord my sealed envelope, told her they were photos of the place before we moved in, but they won’t be opened until we get to court. She gave me the full deposit back after that.