Photographs of a property, sealed the moment they arrive and stamped against world time (UTC), with the location the phone reported and the address locked in alongside. You get a verification link and a finished PDF. Anyone you send it to can check it themselves.
Move in, move out and post repair photographs for California turnovers under AB 2801.
Document the condition of your unit before you hand back the keys.
Rental cars and short term rentals are next. Same engine, different shot list.