Most houses in the Sparks service area went up between 1938 and 2003, with the median build year sitting around 1989, which is exactly when steel track brackets started shipping thinner to cut cost. On a lot of these doors, the brackets were fine for the climate they were rated for but never built to flex through decades of freeze and thaw.
Sparks sits in a cold, severe climate band, and the hard freeze-thaw cycle each winter works the lag screws in the track brackets loose. Wood jambs shrink and swell with the cold, the bracket shifts a sixteenth of an inch at a time, and eventually the track itself is no longer plumb - which is when a roller finally jumps the rail.
Across the five neighborhood pockets built mostly in the 1980s and 90s, the same era of door hardware is now thirty to forty years old and failing in the same way. With 11,782 owner-occupied houses across this service area, most sitting on original builder-grade track hardware, off-track calls are one of our most common jobs - not because the doors are badly made, but because they've simply outlasted the brackets holding them.