Parts vs. Whole
I don't have any vacuums that old, but my general sense is it's more economical to find a complete--or nearly complete--machine than it is to buy a bunch of replacement parts. I'll give a recent example:
This past summer, I bought a Kirby G4 that needed a cord, a headlight bulb, and a back panel for the handle. Instead of spending $40-$50 online for those items a la carte, I went back to the thrift store where I bought G4 and snagged the Kirby Gsix that had been sitting next to it for $20 and stripped it for the needed parts at a considerable savings.
Yeah, the cord and handle panel don't quite match the G4's other plastics, but they don't look bad enough to classify the machine as a 'frankenkirby'. The Gsix had a ragged outer bag, so I felt at least somewhat justified cannibalizing it, but I still, I feel a little bad whenever I go down to my barn and see it sitting in pieces. I have to remind myself that it was purchased as a parts donor, and thus it is serving its intended purpose.
All that said, I have had machines that I paid too much for to start with, and then ended up letting them become money pits as I tried to put them to rights. I've also walked away from machines that 'just needed a couple of things' when I realized just how expensive those couple of things would be. Often, those machines are a better value as parts donors.
