In my "normal" day to day, I rarely use knives. In the wilderness, or in a RECESS situation, a trusty sharp edge is your single most versatile tool.
Knives help you strike fire, forage, make tools, repair gear, hunt, and defend. There is no end to their utility.
Stash them everywhere: in the car, around your home, strapped to every bag, in your kit, and on your person. Non-reflective blades are discrete; and I prefer a combo edge. You don't need to spend a lot, just look for a solid build.

Related