Most of the spring calls we take from Great Falls come from doors that are close to the same age as the houses themselves. Homes here cluster around a 1985 build year, which puts a lot of original torsion spring assemblies at 35 to 40 years old - well past the wind-cycle rating stamped on the spring when it was new.
A torsion spring is rated for a number of open-close cycles, not years, but in a house from the mid-80s that math has usually run out regardless. The steel fatigues, a coil starts to sag unevenly, and one morning the door either won't lift or slams down on the way closed because the spring stopped doing its half of the work. On these older setups we also find single-spring installs on doors that really need two, which loads one spring harder than it was ever meant to carry.
We're driving in from Ashburn, about 9 miles out, so we're not guessing at what's common on this side of the county - it's the same age band of hardware call after call.