Here's the honest limitation: not every door is worth repairing, and we'll tell you that on the phone if it's obvious before we even come out.
If a door is from the earlier end of that 1959-2003 build range and it's on its second or third spring replacement, with a track that's bent from an opener that's been straining against worn rollers for years, you're usually better off replacing the whole unit than chasing individual parts. The same goes for openers built before the mid-90s safety-reversal standards were common - we're not going to sink money into rewiring a unit that's already past the point of being reliable.
A cracked panel on an otherwise sound door, on the other hand, almost always makes sense to fix rather than replace, especially on a double door where swapping one section is a fraction of a full replacement. We'd rather tell you a repair isn't worth it than run the bill up on a door that's already decided its own fate. Across the 29,110 households in this service area, most of the calls we get are repairs, not replacements - but when it's time to replace, we'll say so plainly.