You are paying for the diagnosis, the part, and the labor to put it in correctly - not a flat 'service call' that doesn't go anywhere. A torsion spring replacement is a different job than an opener swap, and a bent track on a door that has been forced open with a broken spring is a different job again. We tell you the breakdown before we start, not after.
With median household income in this area running around $93,635, we see a mix of homeowners who want the cheapest working fix and homeowners who want to replace an aging door outright rather than keep patching it. Both are reasonable, and we quote accordingly.
What we won't do is sell you a full door replacement when a spring and roller job solves it, or talk you into a repair when the door is actually at the end of its service life. The age of your house matters here too: hardware from the 1965-2004 range often needs parts that newer stock doesn't bolt onto cleanly, which can add time.
If a part has to come from a supplier instead of off the truck, we say so up front rather than guessing, so the number you hear is the number the job runs.