Carpentersville sits in the same cold, moderate winter band as the rest of the area, and cold is hard on old spring steel. A torsion spring loses tension gradually with every cycle, and that process runs faster on a spring that's already 40-plus years into service than on one installed in the last decade. Combined with a median build year of 1977, a lot of doors here are working on original or first-replacement springs well past any reasonable service life.
There's an income angle too. Median household income in Carpentersville runs $86,327, well under the $111,898 median across the wider service area. That gap shows up in how repairs get handled - more owners here are keeping an original door running with a spring or roller swap rather than replacing the whole unit, which is a reasonable call on a door that's otherwise sound. It just means the spring and roller wear we see on these calls tends to be further along before anyone calls.