Cold is the other half of it. This is a severe cold climate zone, and steel contracts hard in winter. On a door built in 1986, the steel is thinner than what goes in today, so cold-weather contraction puts more stress on panel seams and hinge screws that have already loosened over four decades of use. Torsion springs lose temper faster in that kind of repeated cold-to-warm cycling too - they don't snap on a schedule, but a spring installed in the 80s or 90s is well past any reasonable service life by now.
Waterflow sits about 16 miles out from Farmington, which matters less for the cause and more for what it means once something fails: parts aren't sitting in a truck two blocks away. If a part needs to be special-ordered for an older door, that order takes the same time it would anywhere in the area, but the drive adds to the day.