Knife Carry can be accomplished in a variety of ways. A pocket Knife, of course, is generally carried in a pocket. In addition many folding Knives are also carried in a pocket although that's not the preferred method of Carry. If your Knife has a hole in the end of the handle (lanyard hole), a lanyard (cord) can be attached which will allow you to Carry the Knife anywhere you want by attaching the cord to X. A neck Knife, is any Knife you want to hang around your neck via the lanyard, and there are Knives specifically designed as a neck Knife. Most Knives (except pocket Knives,) are carried in a Sheath, which allows the Knife to be placed on a belt (traditional,) strapped to gear, the thigh, ankle (boot Knife) or just about anywhere you wish. A Knife Sheath allows the option of carrying the Knife tip up, tip down, sideways etc. How you decide to Sheath your Knife is an important consideration. A Knife Sheath not only protects the blade (and you), but allows instant access and will keep the Knife from getting lost. If you bought an expensive Knife, the last thing you want to do is put it in a cheap Sheath. Additionally, since your survival Knife is your most important survival tool, loosing that Knife because the Sheath you put it in was a POS, could be cause for dire consequences indeed. DON'T SCRIMP ON A KNIFE SHEATH. If the Knife you bought comes with an inadequate Sheath, and many will, replace it with a good one.
Knife Sheaths are generally made from Leather, Cordura Nylon, Ballistic Nylon, Plastic and more recently Kydex. Here's a look at the most commonly used Knife Sheaths.
NYLON SHEATHS: A good Nylon Sheath, whether cordura or ballistic nylon is an excellent, and generally inexpensive method of Sheathing a Knife. Cordura Sheaths are tough, strong, rot and mildew resistant and aren't affected by water. They're also scuff and tear resistant, and are relatively quiet. Nylon Sheaths will stretch a bit over time, which means sometime in the future, your Knife may not fit as snugly as it did when the Sheath was new.
LEATHER SHEATHS: Like nylon Knife Sheaths, Leather Knife Sheaths are tough, and strong. Although they aren't impervious to water, they can be treated to be water repellent. Like Nylon, Leather will stretch a bit over time. In addition, Leather will scuff, cut, and stain. None of which will affect the capabilities of the Sheath. But Leather has advantages none of the other Sheath material has. It can't crack, like plastic or Kydex, and it can't break. Leather can be re-sewn. The nicest thing about a Leather Sheath? They're silent. And they take on character over the years. Don't sell a Leather Sheath short. All things considered, it's probably the best over-all choice for a Knife Sheath
PLASTIC SHEATHS: Unless the Knife in question is a fillet Knife ... a plastic Knife Sheath is not a good choice for use as a survival Knife Sheath.
KYDEX SHEATHS: Kydex is a high performance thermoplastic that is unaffected by water, blood and most chemicals, including skin acids. Kydex holds it's shape and will not stretch or shrink under normal conditions. Kydex is hard, with a Rockwell hardness rating of 90 (much harder than your Knife blade). A Kydex Sheath however, presents an enigma. A good one ... and I want to emphasize the word GOOD, can be superb. But don't let the marketing blitz fool you. Even a mediocre Kydex Sheath can be worse than worthless. There are pros and cons to a Kydex Sheath.
KYDEX PROS: A Kydex Sheath is unaffected by moisture, blood, etc. and is stretch and shrink proof.
KYDEX CONS: Noisy...with a CAPITAL N! Simply withdrawing the Knife from the Sheath makes noise. Banging the Sheath into a tree etc., makes even more noise. Most Kydex Sheaths are not very comfortable to carry. If the Knife fits too tight, or too loose in the Sheath, you will have problems. A Kydex Sheath, unless it has an insert, can actually dull the edge of the Knife every time you put the blade into, or take it out of the Sheath.
Taken as a whole, one would probably say, Kydex is NOT a good Sheath. But you would be wrong. PROVIDING THE KYDEX SHEATH IS OF THE HIGHEST QUALITY, a Kydex Sheath is an outstanding Knife Sheath.
Regardless of which Knife Carry you use, or which Knife Sheath you choose, (or that chooses you, as the case may be,) it's important to remember that a Knife Sheath is only as good as the method used to secure the Knife in the Sheath. And because losing your Knife in a survival situation would be devastating, securing your Knife is as important as the Knife itself. For Sheaths, Velcro closures work very well. If your Sheath only has a simple snap to secure the knife, you should add a Velcro strip, or a lanyard to provide additional protection against loss.