Home electrification changed the house more deeply than any style did. For a stretch of American history, "modern" meant one thing above all: wired. Before appliances and decorative fashion, the deepest change to the house was electricity itself, and it reshaped rooms and fixtures more thoroughly than any style movement.
The shift took decades and left its marks everywhere. Early wiring ran through the house in ways that show, knob-and-tube runs, surface conduit, ceiling boxes cut into plaster after the fact where a room was lit before it was wired. A fixture added to an older house often sits where the retrofit could reach, not where a designer would have placed it. Read those clues and you can date not just the house but the moment the wires arrived.
Electricity changed what a fixture could be. Freed from the open flame, lighting no longer had to vent heat upward or feed a gas line, so shades could close, sockets could point anywhere, and the fixture became pure design. The whole run of styles that followed, Deco, Moderne, mid-century, took that freedom for granted; they were born after the bulb and shaped around it.
The wiring that made all this possible is also the part that ages worst. Early insulation dries and fails, and a fixture beautiful on the outside can be dangerous within. That's the gap restoration closes: keeping the fixture that electrification produced while replacing the wiring that time ruined. The house that wiring built is still worth living in. It just needs its wires brought current, which is most of what we do.