That's the fun part for some...
The restoration part of it. Others, more knowledgeable than I know what machines were made when, how many, you name it. You should see some of the restorations I've seen by other members of this club. Breathtaking! Yes, Virginia, there are folks who collect vacuum cleaners. For many, they represent the changes in industrial design and the fashion of an era. Much like automobiles, furniture, HI-FI systems. Coffee pots. Others are attracted to them by the childhood memories sparked by the machines.
I on the other hand, was kidnapped and forced to work on these machines for other people. I don't even like vacuum cleaners!