DR Laura:
My central AC made it 24 years, too. It would have lasted another year or two, even though we knew it was in a delicate condition. But after we'd had that tornado activity and extended power outages in 2018, it survived that okay and even ran on our generator power just fine. But it didn't survive whatever was going on when the power company was restoring power to the neighborhood. It finally seized up and would not start again. The company servicing it said that it was very possible that a surge knocked it out when they were working on the power, because a few other customers reported the same thing.
As it happened, Nathan owned a few window ACs that are in fine shape and we just put those in the past two summers and have been fine. For the replacement of the entire unit -- the compressor that sits outside the house, and the other half that attaches to the furnace -- I'm looking at about six grand. The insurance company offered so little that I said I'd wait for a while. They won't replace just parts for anything using the old refrigerant, you have to install completely new units. Which is a nice racket. At least I won't be looking at the kind of structural work that you are. What a nightmare.