Lots of people get their gear serviced annually, even though they only did a relative handful of dives. The manufacturers push that hard, and people follow that push. Most of the time the service really isn't needed, but it doesn't hurt, does it?
When I had a regulator go bad during a liveaboard trip trip years ago, right after getting it back from its annual servicing (which I never missed), I was surprised. The shop I used did not service that brand of regulator, so they sent it back to a guy in another whop who did those for him. It came back and failed again. We sent it to the manufacturer (Mares), and they said the problem was that it had been far too many years since it had been serviced. They wondered if it had ever been serviced.
Eventually the problem became clear. Knowing that most regulators coming in for annual servicing do not really need it, the technician at that other shop routinely held on to regs for a couple weeks and then returned them without doing a blessed thing to them.