For $60 it is surely a loss leader to try to find issues to upsell other services. No surprise that the companies that sell it think it should be done once a year, just as Jiffylube thinks you should change your oil every 3000 miles. It's cheap insurance, right? (Has anyone here ever lost a car due to infrequent oil changes?). I am a certified (EPA sect. 609) and equipped auto ac guy, and the principles with home ac are the same. There's not a lot that can go wrong in a year, barring one time events that can't be prevented, and very few preventive items that a homeowner can't do themselves with a bit of research. Most of the service involves visual checks, just like the free or cheap "xx-point inspection" for your cars, which then lead to new brake pads, rotors, batteries and whatever else.
I imagine that at the end of the visit, the tech will let you know that the current going to the compressor (or the fan) is a little high, which is a sign of wear (wow, good thing we caught it in time--you're so lucky!). If the compressor goes out it will be very costly to fix, so you should replace it now to be safe. Of course this will be very costly too, but it's the right thing to do, right? Not so cheap insurance.
Do some research. Then you can either do some things yourself, or at the very least be informed so you can ask the right questions if the tech recommends further service, and try to figure out if there's a legitimate concern, or if they're just using fear to sell you a 10000 mile transmission flush.
BTW, what does a "tune-up" involve in a modern car? Food for thought.
