I started carrying a knife a few years ago, and now I feel naked when I leave the house without it in my pocket. I will add, get a lockblade knife -- one with a blade that locks open. Personally, I prefer a liner-lock mechanism. If you carry a jackknife you are asking for it to fold up and cut your hand when you try to use it. I also recommend that you get a knife without a belt clip, or that you remove the belt clip. They stick out and dig into your hand, and they just get in the way when you carry the knife in your pocket. My knife has a 3 1/2 inch blade. That's about the maximum size that you can carry comfortably in your pocket. Don't try to get too big a blade, or it will be uncomfortable and you won't carry it. The knife has to be there when you need it. Keep the blade sharp at all times, and periodically tighten the pivot screw so that the blade doesn't wiggle from side to side (too loose) or refuse to lock into place when you flick it open (too tight). These screws never stay in adjustment for long, so you will need a small screwdriver bit that fits the screw (usually a tiny hex or star head). You should always have this screwdriver when you buy a folding knife, just as you should always have a wetstone to sharpen the blade on. The best kind of knife is one with an assisted- opening mechanism. These knives have a little tab that you press with your finger, and the blade flicks open and locks into place like a switchblade. You can learn to flick open a knife without the assist, but I like the ease of assisted-opening. But, again, it only works properly when you have the pivot screw at the right tension, and when the blade is clean. Regular maintenance is very important if you want a smooth action.