Being a landlord is not for the faint of heart. I know exactly what you are talking about. There good tenants and bad tenants.
I had a tenant disappear, left mostly junk that I could legally throw away (value less than $250) but in the back shed he left a Harley. I had to store it for 6 months. After that I could legally sell it. Any excess over the storage fees I would have to give to the tenant if they ever showed up. Guy has never showed up (25 years ago).
Two main things I learned:
1) It is a business, treat it like any other business. Every tenant has a sob story, but that does not relieve them of having to pay rent and taking care of MY house.
2) It is better to lose a month’s rent letting a house stay vacant at the beginning, to find the right tenant than it is to lose 6 month’s rent at the back end because you put the wrong person in there. (I got pretty good a picking good tenants.)
I recall one time helping my dad fix up a house that had been trashed. They had painted the kitchen walls black, and spray painted the appliances red! (Back in the early 70’s). All in all though they were pretty lucky, I only recall a few of those horror stories.
A house at the end of our block was a rental and after every renter the guy had to redo the entire house. He finally sold it and a retired couple live there now. Good for him, and good for the neighborhood. The last renters ended up with three families of mexicans - in a two bedroom rambler with no basement!