Collecting Knives by Manufacturer/Maker
This is by far the most common and safest way to collect knives. Many people started liking knives as a hobby simply because of a knife from a company that made them interested. Eventually they buy more knives from the same manufacturer before moving on to other knife manufacturers. Some people are more of a hardcore fan on one particular knife company.
The advantage of collecting knives based on the manufacturers is that one's collection is focused on a particular brand, and this would make it easy to display knives and more importantly keep track of a knife company's various models and manufacturing timeline. Just by picking up an old catalog you can know what knives were produced in which year - a very handy skill for accessing a knife's value.
Busse Knife Collection (Photo: mikeymojo - bladeforums)
Which Knife Companies to start with?
For new collectors, this is the most common question asked. Many people like knives from Benchmade, Busse, Case, Randall and Spyderco, just to name a few. Case knives are by far the most collected knives worldwide and has an unrivaled number of collectors. A very common company that even non-knife collectors know about would be Victorinox, the famous maker of Swiss Army knives. Most people have heard of their knives and even have 2 or more of their knives, which is essentially a mini-collection in itself!
Start with those knife companies that have a large collector group such as those mentioned above. When new to any hobby, it is sometimes wise to go with the flow first. The knife companies should have a fair bit of history and produce knives made with the highest quality. Most of the knives from those companies listed above appreciate in value over the years, but more importantly as popular knives among knife collectors they retain their value over the years.