I have inherited a couple of knife collections over the years and have (not purposely) built one of my own. The results as far as money goes are exactly the same as when I was buying and selling firearms.
If you can buy a gun/knife or anything else collectible at a hugely advantageous price, then you can sell it and make money. Other than that, I learned a few things the hard way. YMMV...
- what is popular today won't be popular tomorrow. Look at all the steels that come and gone with knives where a "supersteel" from two years ago is definitely a "meh" now
- knife brands (and guns) go in an out of favor. The market gets confused and a true investor/speculator won't tolerate that. For example, "did you hear that Benchmade/ZT are having QC issues?" Rumor, smut and hearsay can kill the value of a good product. Truth has nothing to do with it
- Google has changed the game. Incorrect information is the norm. It is easy to find postings and rants from unqualified people that have hurt feelings, an odd lemon, or unrealistic expectations, or simply don't have any idea of what they are talking about. For the guy trying to find out what the opinion is of a product, they realize that maybe several thousand people have seen a review or a video that was slanted to make a person's point that could be damaging to the value of an object. And now that any idiot can use their phone to look up "value" while they are standing in front of you, they can easily be swayed one way or another, but mostly towards the negative. I read years ago that out of 100 people that buy an object, less than one will review/post (bet it's less than that) if they get a good representation of a product, but 3 out of 100 will review/post if they feel slighted
- investments usually don't keep up with inflation. Here is a nifty calculator that I use often when reminding myself of my "investments". Feel free to play around with it (might be depressing if you consider all the other factors), I checked it against other sources and it seems to be pretty accurate:
https://goo.gl/hbQDMV
- If you develop a collection of your investments and want to liquidate, you will be surprised (ask me) at how hard it is to find someone that appreciates your skillful purchasing and acquisitions like you do. I needed some money to help pay for parent's health and really took a bath on some rifles that should have sold for 3X what I got out of them. I patiently tried to sell them one at a time to folks that turned out to be looking for an extreme bargain. I put a lot of effort into it since it was going to a good cause. I gave up, took it to a shop that could sell a true collector's rifle (he had the eyeballs, I didn't) for something close to the expected price. On each rifle, he got about 25% less than I thought, but then I paid him 35% commission to sell them on top of that. He had a couple of the guns for about a year
So lessons learned. Don't buy anything you don't enjoy owning. Don't buy anything you can't flip immediately. Keep up with your market so you will know when it is time to get out. Only buy at a great price; yesterday's highly collectibles are mostly just items of interest now, with only a precious few understanding and agreeing to your personal value of an object. And fewer of those are willing to pay collector's prices for your "treasure".
Robert