San Mateo's housing stock sits squarely in the 1947-1987 window that defines most of the area we work in, with a median year of 1964. That means original one-piece or early sectional doors, side-mounted torsion springs that newer hardware doesn't match, and openings framed before current door sizes existed. Add a mild coastal climate - nothing that cracks wood or rusts steel the way extreme heat or freeze-thaw cycles would - and a lot of these original doors have simply outlasted their intended lifespan through sheer lack of weather stress, not durability. They still work, until the track, cables, or panel seams finally give out from age rather than damage. With about 39,760 households in San Mateo, smaller than several other towns on our route, we don't see the volume of identical tract-built doors you'd get in a newer, larger subdivision - more variation in opening size means more measuring on-site and less pulling a standard size off the shelf.