Fullerton's housing stock mostly dates from the 1960s and 70s, with the broader area's homes built between 1938 and 2012 and a median year of 1964. That means a large share of garage doors in this service area are still running on original or first-replacement rollers, many of them steel on hardware that predates the nylon rollers used almost universally today.
The mild temperate climate here doesn't put doors through the freeze-thaw cycling that cracks rollers fast in colder regions, but it doesn't spare them either. Daily heat cycling on an attached garage, especially one facing west or south, dries out nylon roller stems and hardens the grease in steel roller bearings over years of use. Add decades of daily cycling on a door that's never had the rollers touched, and wear shows up as flat spots, pitting, and cracked stems rather than sudden failure.
Across the 76 named communities that make up this service area, that 1960s-70s housing stock pattern repeats, which is why roller wear is one of the most common calls we get rather than a rare one.