A great reference is in the Co-op Journal portion of this website which gives the history of this concept and its current form - basically, a discussion of the items which allow capabilities in navigation, illumination, sun protection, first aid, repair items (including knives),fire, shelter, food, water, and clothing. Oddly enough, there is no mention of signalling other than personal locator beacons. I always pack a whistle and signal mirror - just the thing when you want others to notice your presence.
The ten essentials has been criticized because there is an implication that simply possessing the items in the list will keep you safe. Like all the rest of the stuff you haul around in the woods, gadgets need to be employed properly and effectively to achieve the desired end.
Consider matches. Used properly, you have warmth and comfort (and you are signalling, as well, if that is your aim). Used improperly, you do not achieve an adequate blaze or, indeed, you may ignite a wildfire of staggering proportions.
An experienced night hiker knows that with proper dark adaptation, especially if there is a quarter moon or better, one can hike safely with only minimal, intermittent use of a head light.
Shelter is a widely variable item. Sometimes one can find a convenient rock shelter or overhang, quite usable as is, with little or no modification, providing superior refuge fro wind and rain. A light weight bivvy sack, used properly, will augment and improve other situations. And so on with all other categories.
These items, all of which should usually be carried routinely, should ideally be versatile, no heavier than necessary, durable and foolproof, easy to operate, and hopefully not too expensive.
Modern electronics improves and complicates the classical situation, Rechargeable batteries are infinitely preferable to alkaline,which tend to leak and corrode the implements in which they are placed. The advent of the cell phone, f one is within range of a cell tower (not always possible, especially in wilderness areas) places a remarkable tool, useful for communication and navigation, as well as other functions. in everyone's hands.
Many electronics, like had lamps, can be recharged directly from a power bank (essentially a large capacity battery). Power banks are often equipped to function as a flashlight or lantern. So one now has the capability to charge up their light or phone, as the situation requires. Doubtless there will be other items with this capability in the future. all that one needs to carry is the power bank and a charging cable.
You can purchase most of these items in various preassembled kits, something I discourage. I much prefer buying items one by one, getting the things that suit your individual situation. Be sure you use them regularly. In a tough situation, you don't want to deal with an unfamiliar gadget.
In any case, be sure that your gear and capabilities are adequate for the trip, however many essentials you have.
@hikermorIs this the article you're talking about? https://www.rei.com/blog/hike/10-essentials-every-hiker-always-carry
How did you learn about the ten or twenty or thirty essentials? Any tips for people who could use help learning how to use some of those items, not just carry them?
Truth to tell,I think I learned about the essentials the hard way, like most of us do. I began climbing and hiking in college and I ran across "Accident sin North American Mountaineering"" an annual publication. It had thoughtful, thorough analyses of accidents. This,along with some day hikes that extended into the evening, etc. got me started carrying items like matches and an extra sweater.
Later I purchased the first edition of mountaineering: - Freedom of the Hills which is full of good advice. About this time I became heavily involved in an extensive search for three Boy Scouts who walked into an epic and unpredicted storm and perished. This was the beginning of a long commitment to volunteer search and rescue.
One thing became clear while doing SAR - the majority of our victims lacked knowledge and appropriate skills and were often inexperienced. We were often called out during weather and times that were unfavorable and I got used to gearing up for very bad conditions. There were plenty of occasions during which we had to improvise.
As a hiker and backpacker who obviously likes a lighter pack rather than one that is heavy, I abhor redundancy. There is one exception, however. I typically have at least three means of lighting a fire,often tremendously useful in many ways.
One thing surprised me about the fine article you referenced. There is no mention of a knife or cutting instrument,almost always discussed as a component of the ten essentials. These days I usually carry a multi-tool (in the city as well, when I can). Before I encountered my first multitool (the REI in Los Angeles, about 1985) I routinely carried a Swiss Army Knife. You don't need a huge Rambo style blade, but you often have to cut up things or tighten loose screws, etc.
I am always happiest in a pinch when i can get my hands on a familiar gadget that I have used successfully in the past and put it to work. Most items have some sort of a learning curve and it is best to get that out of the way before the situation is critical.
I usually carry my ten essentials with me whether I am backpacking for several days or kayaking, cycling, or hiking just part of a day. I think you raise the importance of two essentials that weigh nothing: experience and common sense. Ten essentials might not do anyone any good if the person needs them but does not know how to use them and to improvise and think outside the box.