If you are going to a bike shop once a year for maintenance, then you are doing the maintenance you should be doing. But many people have old bikes with rusty

If you are going to a bike shop once a year for maintenance, then you are doing the maintenance you should be doing. But many people have old bikes with rusty brakes, non-working gearing, and just go on using them until they fall apart. Also, different bikes require different levels of maintenance. And your riding style and frequency of use affects the speed of wear.