The median home here was built around 1972, a decade earlier than the wider service area's median of 1976. That gap matters more than it sounds like it should. Doors from this window were almost always installed with side-mounted torsion springs on a single, heavier torsion tube, not the double-spring setups that became standard through the later 1970s and into the 80s.
That older side-mount design uses different cable drums and a different winding cone than what's on the shelf at most suppliers today. When a spring snaps on one of these doors, we're often matching hardware rather than grabbing a stock part, and that adds a little time to the job.
Cold-climate stress compounds it. This area sits in a severe cold band, and steel torsion springs lose temper faster through repeated freeze-thaw cycling than in a milder climate. On a door already running original 1970s-era springs, that shows up as a spring that lets go with no warning on a January morning rather than a slow, audible fray.