The buildings and the hardware
The buildings you’ll see around here often put specific demands on hardware. Older wood doors and frames may be warped or have mortise pockets that take a different lock body than modern bored locks; those installations require cutting, shimming, or swapping to a compatible cylinder and strike. Apartment and rental units tend to need rekeys or keyed-alike systems for tenant turnover, while small retail spaces may use heavier-duty rim cylinders, exit devices, and bolting hardware that needs routine adjustment. Knowing how a door and its frame behave is half the job; correct alignment and the right strike plate matter as much as the cylinder.