There is something extraordinary about building a pocket knife collection. Jack's knife is very useful. You don't need packaging, you can take it anywhere, and storage is easy. Jackknives are less intimidating and often less expensive than their fixed knife counterparts.
Given the impact of 9/11 and airport security concerns, carrying a pocket knife in luggage still attracts less attention and suspicion than a fixed knife. You can get more information about folding knives via https://cherrycutlery.com/case/case-hunting-knives/.
Considerations for collecting folding knives
There are a number of considerations that go into creating your knife collection. Are you interested in a particular brand of knife, for example, buck, case, or other well-known manufacturers? Collectors build collections around knife styles; Standard folder assisted openers and multi-bar variants.
Other factors may be important to you. Some collectors choose folding knives based on the type of steel, the shape of the blade, or the locking mechanism used for user safety.
Other, more practical factors include use; a portfolio can be a utility knife commonly used to perform a task, or it can be a knife displayed for craftsman pleasure for beauty or investment and never used.
Know your jackknife collection
Serious collectors are more than just collectibles. If simple collection is your number one goal, you'll still want to catch up to the folding knife market. It is best to read about knives that interest you. Blade magazines and recent works are a good place to start.