The buildings and the hardware
The local housing stock affects hardware choices and common failures. Many doors are older plank or stile-and-rail wood, and frames can be out of square; that leads to latch misalignment and thin strike plates that pull free under force. Apartment buildings bring keyed-alike or master-keyed systems and cylinder types that need careful handling to avoid cross-keying. Newer construction and renovated units use bored cylindrical locks and tubular latch sets that are lighter and prone to wear at the latch face. Knowing whether a door has a mortise pocket, a bored hole, or an aluminum storefront frame changes which parts fit and how a lock is repaired or upgraded.