This happened to my wife's parents. Well, sorta. They own 16 condominium units across two complexes. Overall, they have earned about 12x what they put in. All the mortgages are paid off. They only have to cover taxes and the HOA dues. The rest is gravy to the tune of $1,200/month/unit. Since they bought in so low, they see a 100% return on the investment every two years. This is their retirement income.
They rented one unit to the same guy for 17 years. When he was moved out by friends to an assisted living facility, the place was totally trashed. Totally. There was an unreported leak that damaged drywall and rotted out the framing, there was a roach infestation, the refrigerator died at some point and the food rotted. They had to spend about $50k gutting the entire unit to the studs and beyond. Though, to be honest, they were going to do that regardless of the condition of the unit in order to update it and enable a $1,600/month rent.
Edit: Unfortunately, my wife has a sister, so we only have half of the units bequested to us.