The climate here runs cold and severe through the winter months, and steel contracts in the cold the same way any metal does. On a door built around 1989, the torsion spring has had three decades of that cycle - tight in January, loose in July - and metal fatigue from that swing is the single biggest reason springs here fail when they do, usually on the coldest mornings rather than mid-summer.
Across Sun Valley's roughly 6,941 households, most sitting on that same 1980s-90s stock, we see the same handful of failures over and over: springs rated for one era of cold-weather use finally giving out, cables fraying where they've rubbed the drum for years, and rollers that were fine for a decade and are now the thing that's grinding.
We can't point to a single bad batch of hardware or a manufacturer defect - we don't have records tying any of this to a specific installer or builder from that period. What we can say is that age plus cold is a predictable combination, and it's the one we plan the truck's parts around when a Sun Valley call comes in.