This all started when I got interested in the BOYE display case, and decided to collect one machine for each item in the case (I'm still missing one - WW#8). And after getting a few and learning about the attachments, I got fascinated by the differences between them - I also wanted one set of attachments for each machine I have. It's rare to find a set with everything in it, so often I'd end up with 2-3 boxes to get a complete set. And I also started collecting different sets that I found.
I've pretty much moved from the "acquiring" stage of my collecting, and now I'm on to the organizing and codifying stage. I'm working on documenting the differences and when I get it complete (which is going to take years) it will be available on the Victorian Sweat Shop site. BTW - that is not my site, just where I've decided to put information.