For a neighborhood built mostly in the mid-to-late 1970s, we carry torsion springs sized for the heavier single-piece doors common to that era, standard-lift cables, and the steel rollers that replace the nylon or steel originals once they've started to flat-spot. We also stock weatherstripping and bottom seals, since rubber from an original 1976 install has long since hardened and cracked in our climate. One honest limitation: if a door still has its original opener from that period, we don't keep obsolete circuit boards or control panels on the truck, and sourcing one can mean a wait of a week or more, if it's available at all. In that case we're usually talking about opener replacement rather than a repair, and we'll say so rather than stringing out a maintenance visit pretending otherwise. For spring work specifically, we match wind and wire gauge to the door's actual weight rather than guessing off age alone, since not every 1970s door in this stretch carries the same panel material.