Think how you felt when you found a 1997 Purepower Autosense - it was like hitting the jackpot, a rare machine that no-one else has, and the seller posted it to you. Then I can imagine that sinking feeling when you opened the parcel and that flaming Royal Mail had damaged it in transit, and the subsequent trawl to then find a new chassis.
Its the feeling you get when you find a rare machine and win it that keeps us collecting more and always on the lookout on ebay for bargains. I spend hours on ebay looking through thousands of machines for that odd diamond in the rough, and when one comes up, its very exiting!
So, I say never throw out an old rare vac if you can at all help it, because one day, that elusive part might just crop up on ebay to fix it with. Put it into long term storage in the loft and always keep an eye out for the part it needs.