I have been in the same rental house for many years.
In the years that I have lived here, I have only ever had one issue with the heating and cooling system.
Because there is only window units and space heaters, there is not much that can go wrong. The weather in the region where I live is mild, and gets warm in the summer. The house I live in is well shaded and there’s a lot of trees over the house. The sun never makes the house too hot and I am happy that I live in a house that doesn’t get baked in the sun all day. When I noticed that something was wrong with the AC, I acted fast. I know I didn’t want to be without AC for more than a few days, and I was looking forward to a new AC unit. The ones that were in the house before the replacement were 10 years old. The AC units were rusted and had slowly stopped blowing cold air. It wasn’t that much of a problem until a new family moved in next door and took down one of the trees that was providing much of the shade that was keeping the house cool. I didn’t notice how much sun they were blocking until they were gone. The AC units were replaced in about an hour and we were able to sleep comfortably that night regardless of the lack of shade in the backyard.