Well, I visited a local gun show on Saturday, and saw a friend of one of my friends. This guy is a big time knife nut, and I showed him not only the knives I had on me to trade, but the knives I had in my pockets. I showed him a Northfield Missouri Trader, the Bladeforums 2012 trapper, a two blade TC barlow that Charlie spear headed (no pun intended), a one hand wonder, and I still had another knife being sharpened, and another knife in my pocket. Now, granted, most of these were just to show off, and the only one that has seen much use has been the barlow and the other one handed wonder in my pocket. The one that was getting sharpened has seen some miles too.
Our mutual friend believes in the laws of three. Three is two, two is one and one is none. Granted, I am a big guy and I am not always getting out into the "wilds", yes, there are some wild places left in the Mason Dixon area of MD/PA. I can get by with a peanut or other small folder, but I like to carry a larger knife. I don't really need more than one, but I like to have that option. One of my favorite carry options is a small fixed blade usually carried around the neck in a Skookum style rig, and a SAK, mainly on any long walks, or hikes. Why two blades? I don't know, maybe because I can. I usually have at least a SAK or old timey folder, a larger one handed wonder and a fixed blade.
I guess that's why some members on here prefer to carry a knife with two blades. If one breaks, you still have the other blade to use.