Some people carry Swiss Army knives for their convenience and the solutions they offer to everyday problems. However, when you're doing that, you're still carrying a knife, and it's one extra thing to keep track of when you're going about your business. An alternative suggestion is these wallet sized multi-tools, available now in the Boing Boing Store.
The size of a credit card, one of these tools fits conveniently in your wallet, providing you with eleven simple tools on one durable stainless steel sheet. It can function as a can opener, knife, screwdriver, ruler, bottle opener, 2-position wrench, saw blade, 4-size wrench, directional auxiliary wrench, keychain hole, and a butterfly screw wrench. While you almost definitely will not need all of those tools on the same day, it doesn't hurt to have them.
You can get a two-pack of the multi-tools, plus protective cases for each, for $9.99 in the Boing Boing Store now.