A lady I used to work with had to take a day off work one day; I assumed she was feeling under the weather, so when I saw her the next day, I asked how she was feeling.
She explained that she had not been sick, but rather, she had to stay home because the HVAC repair guy was scheduled to come out.
She traveled a lot for work, and when she got home from her most recent trip, she walked into a hot and humid house. It seemed that at some point while she was away, her a/c had called it quits. The HVAC maintenance guy came in as scheduled that morning, but the damage was pretty extensive, and she had to get a pretty pricey a/c repair. I think they had to replace the a/c condenser and maybe a fan or two, as well as something to do with the thermostat. I know she was shocked when she got the HVAc repair bill that day. The guy that did the repair spoke to her about their annual HVAC maintenance plan while he was there, and she purchased it. She told me all about it, and that was the first time I had ever heard of such a thing. It is a service agreement that provides an HVAC tune-up every year, regular maintenance, and free service calls if something breaks. I never knew you could get an HVAC tune-up, just like you do on your car, and that was the first I had ever heard of it. Now that I know, though, I have decided it is a good idea, so now I get the heating and cooling maintenance agreement, too.