I've gotten more recommendations for a particular pocket knife than any other tool. Knives are the original tool; everyone has one, and after 10,000 years there's endless variety. They are intensely personal, too. I've seen and tried many of the suggested knives I've received, and I've published a few of the more well-proven ones.

So, after many trials, here is the one I actually carry: it's a dollar plastic box cutter. There is no knife lighter weight, none cheaper, few as sharp, and not very many as quick. I can open it one handed in less than a second from the moment I reach for it. It is as fast as a sheath knife. Keeping its edge a razor is as easy as nicking off the tip. This plastic snap blade is as thin as a pen and so light that I carry in my pants pocket without even knowing it is there; no special holster needed, and it won't wear the pocket out. It's cheap enough that I hide one in all the clothes I ordinarily wear. I'm not afraid to lose it, and yes, I keep it away from airports.

The cheaper the version of the box cutter the better. You don't want rugged metal ones, like those offered by respectable tool companies; they are bigger, heavier, costlier and no better. What you want is a cheap all-plastic made-in-China throw-away that should cost about a buck. Mine are day-glo orange for easy retrieval if I lay one down.

Other than it being butt-ugly I can't think of why I would want one fancier. I use this one at least 5 times a day, and its quick handiness gives me pleasure each time.

-- KK

Plastic Snap Blade Knife
$2
Available from Amazon