We don't have a flat number to quote you here, and we're not going to make one up. What drives the cost on a maintenance visit is mostly what the opener needs: a basic lube-and-adjust job is quick, but if a circuit board or a sensor needs replacing, parts for the newer dealer-grade openers common in this area sometimes take longer to source than the generic big-box models.
That's the honest limitation worth saying out loud: if your opener is a less common brand that came with a custom-built home, we may need to order the part rather than carry it on the truck, and that adds a day or two to the job. We'll tell you that on-site before we start anything, not after.
With a median household income of $101,534 in this area, we also see more of the higher-end dealer-installed opener models than the stripped-down builder-grade units that went into some of the older subdivisions closer to Sioux Falls. Those units aren't more failure-prone, but their boards and sensors are specific to the brand, which is the main thing that affects parts cost and wait time.