I clean the condensing coils during annual maintenance. The tip about cleaning filters is right on the money. I found out the hard way. On this coach it has ducted air and the air intakes are a lot smaller than the screen on the bottom of the AC. Last year I thought the rear air had quit working or was just on low cool. I got to checking and the filters were badly clogged. It had ben less than a month since they were cleaned. After cleaning they cooled much better.
Today I had the AC on while I was mowing at my property where I keep my coach when I finished at noon it was 103 out side but 76 inside, it felt REALLEY GOOD.
Bill