The area sits in a cold-severe climate band, and that's the thing that actually breaks parts here, not just age. Torsion springs lose tension and get brittle faster through repeated hard freezes than they would in a milder climate, and steel rollers that aren't sealed will start grinding once grease stiffens up in January. On a 1964-era house, if the original springs are still in, they've been through six decades of that cycle - we've seen them hold, and we've seen them snap clean on a cold morning with no warning.
The other complication is sizing. Doors built in the 1960s sometimes used dimensions that don't match what's stocked today, so a spring or a track section that would be a same-visit fix on a newer door can mean a special order here. We won't force a standard part onto a non-standard door - it's a fast way to strip a drum or bind a track, and it doesn't actually fix anything. If a door in this bracket needs more than routine maintenance can address, we'll say whether repair still makes sense or whether the age and wear point toward replacement instead.