The most common surprise on a 1961-vintage opening is a header that was framed for a single-layer wood door, not the insulated steel or composite doors sold today. Steel sandwich panels run heavier per square foot, and if the original springs or track brackets were left in place from a prior swap, they're often undersized for the new door's weight - that shows up within weeks as a door that reverses on its own or won't stay up.
Another one: openings on homes built right around 1961 sometimes have a shallower head clearance than the newer double-track openers need. If nobody checks that before ordering, the opener gets bought first and the clearance problem gets discovered on installation day, which costs everyone time.
With 4,808 owner-occupied houses across the service area, we see this specific mismatch often enough that it's now the first thing we check, not the last.