For Homer Glen calls we carry torsion springs across the common residential weight ranges, standard nylon and steel rollers, and both chain-drive and belt-drive opener parts, since houses here run a mix of original 1980s hardware and later opener swaps. We keep photo-eye sensor kits stocked specifically because of how many older openers in this build era never had them added.
What we don't carry is a full stock of every discontinued panel design from the late 1980s - if a single cracked panel needs matching on a door that's otherwise sound, that part sometimes has to be ordered rather than pulled off the truck, and we'll tell you that on site rather than promise a same-visit fix we can't back up. Cold-weather steel and hardware here take the same seasonal stress as the rest of the region, so we also carry weatherstrip and lubricant suited to that swing, not just summer parts.