Berwyn's houses have a median build year of 1938, which puts a lot of the neighborhood a full generation ahead of the 1963 median across the wider area we cover from Skokie. Doors going into openings that old were sized to a narrower standard than what's sold today, and the framing around them was built for a lighter, single-layer wood door - not the insulated steel or composite sections that make up most new installs now. When a homeowner in one of these houses finally replaces a door that's been patched for years, the opening itself is often the problem: out of square, undersized, or trimmed with jamb material that won't hold new hardware without extra work. We don't guess at this from a truck. Every Berwyn install starts with measuring the actual opening against the door going in, because on housing this old, assuming the rough opening matches a modern standard size is how a job goes sideways on install day. This region also sits in a cold-moderate climate band, which matters for how a door on an opening this age gets sealed once it's in.