Across this service area there are about 29,245 households, with roughly 15,449 of them owner-occupied, so most of what we work on belongs to the person who answers the door. The housing stock skews older, built mostly in the 1960s and '70s with a range that runs from 1958 to 1991, which is why we carry hardware sized for both ends of that spread rather than assuming everyone has a 2015 insulated steel door.
That age spread means two houses on the same block can need completely different parts. One still has its original extension springs; the next had a torsion conversion done at some point by a previous owner or a repair that never quite matched the door's weight. We see both setups often enough that neither surprises us, and it is why we ask when a house was built before we guess at what is wrong with its door.