I agree that loosing a knife is a bad thing. If you have knife with a wooden handle and a leather sheath the tolerances in manufacturing may still be big enough to allow it to slip out of the sheath. After all both materials tend to change size slightly when they dry or collect moisture. I´ve seen knives of one type where the fit in the sheath for the specimen varied from really loose to much too tight. This is why I prefer to buy where I can pick one that´s just right.