Not knowing what they have.....
It's true, about a lot of stuff. I got Lenox crystal glasses...dirt cheap. They could NOT have known what they really were.
As far as vacuums,they see "old" and send it along. They see "dirty" and do the same.Their lack of sense is our gain. Sometimes, all they need is a good cleaning, belt, bag, etc. Sometimes, we'll buy a bad machine to get a decent, maybe perfect bag.
Some folks 'poo poo' the idea of thrift stores, only buying new, etc.
But, how many of us have gotten wonderful, hard, almost impossible to find items. Trust me: IF the 'right machine came their way', I doubt they'd 'pass it up'. Or, maybe they would. Again, their pass up is our gain. WE all have cleaners we'd love to have, Hoover, and ALL of the OTHER species. I've even bought machine, non Hoover, for other people, because I KNEW they were important to THEM. I was given carte blanche at Vac Way in Scranton. I had a certain amount of time to 'get anything you can'. And, I was careful what I took. Who is the fool who'd pass them up?