The median home in this part of the service area went up around 1979, which puts a lot of Monticello's garage doors squarely in the steel-roller, raw-track era before nylon rollers and sealed bearings became standard. Those original rollers weren't built to run thirty-plus years without attention, and most never got any.
The climate here is mild with occasional freezes rather than hard winters, so the usual cold-snap cracking we'd flag in a harder climate isn't the main driver. What does the damage is the steady, unremarkable wear of a door that's opened and closed thousands of times with a dry bearing - the kind of wear that doesn't announce itself until the roller is already grooved. Houses in this area, like a lot of the broader 1980s-90s housing stock across the territory, were built to a standard that assumed a homeowner would eventually replace the rollers once. Most never did.