It mostly depends on price. For me, if:

1) It's an item I know was used on Fujis of the vintage I or my Fuji buds like or
2) It's an item I know has wide appeal for the possibility of trade or resale or
3) It's a vintage bag, bottle cage, or other accessory...

AND the price is a killer I'll buy it with no current use in mind. If I have a current use my price tolerance rises.