The buildings and the hardware
The local housing stock affects the hardware we use. Where doors are older solid wood or have mortise lock preparations, we pull mortise cylinders or fit new mortise locks rather than swapping simple cylindrical deadbolts. In apartment complexes you see more keyed-alike suites and narrower jambs, which changes latch backset and strike sizing; in newer single-family houses you often find pre-drilled holes that accept standard deadbolts and handlesets. Storefronts and metal doors need heavier-duty latch guards, rim or panic hardware, and sometimes HD cylinders to resist prying. Door type, jamb width and whether the frame is metal or wood determine the parts and installation technique.
