I'm not qualified to respond to the "soldier" part of the question specifically, not having been one. In general I want those who know what they really need to have it.. but this is really a much, much broader question. "Need". There are many ways it gets defined casually, and some of them are IMHO silly. There are some traps that always come up in discussing "need", and a few have come up here. Trap 1: Let's take it out of the realm of what some people want to take away from us (at least so far), and talk about my flashlight. I carry one all day every day, and use it several times a day. It makes my life tremendously easier, EVERY task is much easier if you can see clearly, but before I tried carrying one I didn't miss it at all. I just took it for granted that I had to work with available light and fumble and struggle for however long it took, or rely on being able to just cross a room and "flip a switch". Even though it's something I use CONSTANTLY now, and greatly rely on, if you had asked me five years before I started carrying one whether I "needed" to carry a flashlight I might have argued that I did not. The fact is, I did, I just didn't know it. On this principle you can even ask a bunch of people in the field what they "need" and get wrong answers, they might not know what they're missing. Trap 2: Not too long ago, in another venue, I had a guy actually argue against my practice of tossing a sleeping bag, parka and boots in the back of the SUV in winter, just in case I get stranded in the vehicle in the cold. His argument was that it was SOOO unlikely that I'd need these things that it wasn't even worth the trivial effort of putting them in the vehicle. I consider his analysis to be faulty. Any danger has two components, the chances of something bad happening, and the cost/damage if it does, They get labeled different ways in different fields, I usually call these "risk" and "exposure". This is a classic tiny-risk large-exposure situation, there's very little chance I will actually need these things, but there's really no limit to my exposure, if I do end up needing them and don't have them I may die, others with me may die. Someone who has NEVER had the infrastructure fail them or been thrown on their own resources in bad conditions in their entire lives may see that as silly. These days, a lot of those people survive just fine and pass on the knowledge that come from their "experience" to their kids, so we've got entire generations who view being prepared for ANYTHING as silly, they don't even dress for cold or rain and they buy cars without spare tires.. and these people all seem to feel entitled to pass judgement on what I really "need". Trap 3: I carry a little "emergency" kit daily, and a different kind in the vehicle. On the rare times I pull it out I sometimes get questioned as to how often I "need" it, how often there's a "real emergency". The question is fallacious on the face of it, the kit prevents situations from becoming emergencies, it turns them into mere inconveniences instead. That is has done often, and thus I have fewer emergencies than others. Arguing that I don't really "need" it because "emergencies" are so rare when i have it is circular reasoning. Trap 4: The knife has been probably the most fundamental tool invented by our species. It is literally the most basic of tools, and as a near-helpless species without either claws or fangs, a species that must rely on tools for even the most basic functions, it is the first and most fundamental step in enabling ourselves, stepping up from total helplessness. The more primitive things get, the clearer the necessity is. You won't "need" one until/unless you do, and then it's too late. These days it's not hard to live an entire life without ever NEEDING one, but when things do, however rarely, get that basic, for whatever reason... well, the people who really NEEDED a knife and didn't have one, maybe they didn't ever recognize that need, maybe they wouldn't have known what to do with one anyway... they aren't around to chime in, are they? We've become an entire culture based around learned helplessness, around dependence, and that culture seldom misses a chance to criticize or ridicule any attempt at self-enablement or independence, right down, in the cites, to wearing a hat in the rain. The problem is that with cultures, as with individuals, that works until it doesn't. Otzi the "ice man" carried a knife as a key part of his kit 9,000 years ago, as did most of our grandparents or great-grandparents and EVERY generation prior. It's no accident. We, the ones that can usually get by being this helpless, are the historical anomaly, not them. IMHO, IF (and it's a big "if") there are still humans in human bodies on this planet a thousand years from now, I think it almost certain that they will be carrying knives. It is far less certain that they will be descended from a culture that did not.