We keep common torsion springs, standard rollers, and cable stock sized for the door widths that were typical in the late 1980s, since that covers most of what we run into here. Openers from that era are a different story - some of the chain-drive units installed new in 1989 are long out of production, and if a control board or a specific gear kit for one of those old openers has failed, we sometimes have to order the part and wait rather than fix it on the same visit.
That's the honest limit: on hardware this old, not every component is sitting on the truck. When that happens, we'll tell you up front whether it makes more sense to wait on the part or replace the opener outright, and we won't push you toward the bigger job just because the small one takes longer.
For the door itself - springs, cables, rollers, hinges - we're usually equipped to handle the maintenance and the repair in one visit, since that's the hardware we see most often coming out this way from Punta Gorda.