The service area sits in a cold-moderate climate band, which is mild by national standards but still cold enough that weatherstripping and seal condition matter on any panel we swap in - a new panel seated against a dried-out bottom seal will still let air through even if the panel itself is perfect. We carry standard seal stock and check it on every visit regardless of what brought us out.
For a 4-mile trip from Tukwila, we bring panel stock in common widths and gauges, plus the hinge and roller hardware that tends to fail alongside an older panel, so a straightforward job doesn't need a second trip. What we don't carry on the truck is a panel matched to 1960s-era spacing - across the roughly 71,219 owner-occupied houses in this service area, that's a small enough share of the stock that we order it once we've confirmed the exact measurements on site, rather than guessing and hauling stock that won't fit.