Union City's housing stock centers on 1979, which puts most garages here a good ten to fifteen years ahead of the older tract housing closer to the bay. That gap matters more than it sounds like it should. A door built in the late 1970s is usually on a torsion spring setup rather than the older extension-spring designs, and the opener - if it's original - is a chain-drive unit from a manufacturer that may or may not still stock parts. By 1979 galvanized steel sections had mostly replaced the wood panel doors of the decades before, so what we're usually pulling apart in Union City is steel, not timber, and the failure points are springs, rollers, and drums rather than rot or warped panels. Across the wider area we cover, the median build year runs closer to 1981, so Union City tracks close to that but isn't identical - homes here skew slightly earlier, which means slightly older torsion hardware on the ones that haven't been touched. None of this is dramatic, but it's the difference between guessing at a fix and knowing what's actually behind the panel before the truck leaves Livermore.