Based on my own experiences, a good knife is probably the single most important piece of survival equipment a person should always carry, along with a good fire striker.
Any time I go into the wilderness I have my bush knife on a cord around my neck and shoulder. I wear it like a satchel or shoulder bag. This keeps it handy on my chest when I need it, and worn in this fashion it doesn't flop around when I bend or have to climb or something. It's much easier to re-sheath too. I don't have to turn half way around and fumble with an unseen sheath on my belt.
It's a heavy knife between 9 and 10 inches long with a good, thick blade that can handle splitting wood, shale knapping, pounding nails, and pretty much any other abuse I have thrown at it. Honestly, unless I lose it, I can't see this knife ever needing to be replaced. In my pack I carry a small folding Buck and a Leathermans tool which has a very good smaller blade. There is also a machete that lives in the Jeep. Lol, if the whole world broke wind at once, I can knap a sharp stone pretty quickly too.
Another small folding knife and my flint striker are in my pocket at all times. Even grocery shopping. You never know when you might need to whittle a shelter and start a small camp fire in the frozen foods aisle :tinysmile_grin_t: