not just on alone, but with all of the "bushcraft" and survival stuff. Instead of wasting half a day building a primitive shelter (which is often not feasible cause you're sick, injuried, or lacking in needed resources) carry 1.5 lb of tarp, stakes, cordage. Instead of all the flintknapping, carry half a lb of modified Leatherman Crunch, with some saw blades to be held in the visegrip of that tool. Instead of endless bs about primitive fire-making, carry a couple of ozs of lighters, ferrorod, and wallet fresnel lenses. That's going to give you thousands of fires and you can just bed your coals if you're staying in one place. You're going to die of tooth problems long before you have to worry about not having the easy means to light a fire. You're going to have LOTS more problems, notably with staying dry and warm, and uninjured and adequately fed, 1000x sooner than you're going to not be able to start a fire with the above listed tools.. If you carry 3/4 lb of modified SOL Escape bivvy and 1/2 lb of UCO candle lantern and BEESWAX candles, and are dressed adequately for moving around out there, you'll be able to handle sleeping out there, given a fire, that is. That's a total of 3.5 lbs of gear to replace all the flintknapping, shelter building, debris-bed building, friction fire bs. That stuff is never going to save you if you've been dumb enough to go into the woods without proper gear. Sometimes you only have a few minutes in which to deal with a problem, before the cold, etc, renders you unable to help yourself. I consider a lb of trekking poles to be worth more than all the medical kit you can carry, since the biggest threat, really, is a badly sprained ankle or knee, or a broken leg. If you can't get to some wood to splint that bone, and get to water and out of the elements, you're in real trouble, especially if it's cold. The trekking poles can get you to wood, one can be cut and make a splint, while the other one is your "crutch". and it can also hold up the tarp, keeping rain off of you.