I disagree!

In a survivalist situation you might want to have only one size battery; but for a 72 hour PSK what does it matter what size the batteries are? I have spare lithium batteries in my CamelBack PSK. Battery consumers are specialized. The Photon, Petzl Zippka, SureFire, mini AM/FM radio, strobe light, etc. I’m not trading my cool gear for bigger stuff just so they all use the same battery. If I were stuck in a foreign country that would be a different issue. On the other hand I do avoid things that take weird batteries.
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Thermo-regulate, hydrate and communicate.