Torsion springs are rated for a set number of open-close cycles, and most original springs in Tualatin's 1980s and 90s-built homes are well past that rating by now, even on doors used once or twice a day. A spring rated decades ago for a given door weight doesn't know how old it is; it just fails when it fails, and COLD moderate winters add stress because steel contracts slightly in the cold, changing the tension just enough to push a marginal spring over the edge.
It's not just age. Houses across this part of the service area, with housing dating from 1964 through 2006 and most of that falling in the 1980-1990 window, were built to door hardware standards from that era, which weren't built for forty-plus years of daily cycling. We also see steel cables stretch and fray faster in homes that sit in colder pockets through the winter months, since the metal doesn't flex the same way it did when installed.
One honest limitation: if a spring has already snapped and the cables have jumped the drum, that's not a same-day adjustment - it's a full spring and cable replacement, and depending on parts on hand it may mean a short wait for the correct size.