Honestly? We have no idea.
Okay, that's not a very helpful answer to your question. But over the years we've seen many knives we thought would increase in value and didn't, while other knives we considered pretty ordinary now bring premium prices on the collectors' market.
So-called "collector knives" -- like any collectible, really -- are hard to forecast. We can, however, present a few general characteristics that may make a knife collectible:
- Rarity or uniqueness
- Historical significance
- Condition (relative to comparable or related knives)
- Quality & craftsmanship
- Provenance (who owned it, who made it, what movie it was in, etc.)
- Place-in-production (first made, or last made)
These factors (among others) may affect a knife's value, now and in the future, but there's no formula and there are no guarantees.
Oh, and one more thing: Knife collecting probably isn't your ticket to a worry-free retirement.
Your best bet, perhaps, would be to "plug in" to Internet discussion forums, join collectors' groups, visit second-hand shops and attend flea markets. Knowledge is your best friend, and you'll quickly learn that the marketplace (not the owner) determines the value of a particular knife.
Now, although we're not appraisers or market forecasters, we'll leave you with two suggestions:
- Collect knives that you actually like.
- Don't forget to have fun.
And that, ultimately, is the best reason to collect knives -- because it's fun.