Let me elaborate on what I said earlier, think about priorities. The rule of 3s, 3 minutes without oxygen, 3 days without water, and 3 weeks(+/-) without food.
So with that in mind, keeping warm/cool and hydrated should be your primary concerns.
A reliable way to gather, store, transport, and purify water should be #1 or 2 on the priority list.
Shelter is #1 or 2 depending on your environment, if you live/go out n about in a place that gets very cold and or wet, I'd say shelter is your #1 concern as you'll die from hypothermia well before dehydration in those conditions.
If you're in the desert like me, water becomes #1.
Fire is next, practicing fire craft is the most important element. Find 3 methods that you are comfortable with making fire. And practice with them. Then carry all 3. One of mine is a road flare, no kidding. I cut down a regular road flare and duct tape the end.
Next on the important list for me is wound management, this goes back to the rule of 3s. I keep liquid bandage, sutures, and duct tape in my Pocket FAKs, and my sheath based PSKs.
Hemostatic guaze, pressure dressing, splint, cravat, and compressed guaze all roll with my 10 essentials.
Good tweezers and a fresnel lens, a splinter can fester and become infected quickly, resulting in fever and nausea or worse.
These are some of my thoughts on 10 essentials/PSKs.
With a sheath based kit, KISS applies, keep it simple stupid. I carry a Ferro rod, striker whistle combo, mirror, fatwood, mini bic, duct tape, sutures, liquid bandage, alcohol swabs, benzoin, nails( for shelter building) compass, aqua pouch and aqua Mira, flare, 550 cord
Hope this helps.
