As a talisman around my neck, I wear a glass magnifier.
Now where ever and whenever there is sun, I can make myself a fire
and cook food I have scavenged to kill any harmful bacteria,
or boil water free of all parasites that can cause dysentery and diarrhea,
or for the warmth my body needs to prevent possible hypothermia,
or as protection from any local life threatening wild predators.
As an added precaution I also always carry a disposable lighter,
in case darkness falls upon me before I can make my campfire,
but I only use my disposable lighter very rarely.
because it will run out of fuel eventually
and anytime I need fire when fire can't be
is an official life threatening fire emergency.
You won't have any chance of surviving in the wilderness successfully
if you don't make harnessing Fire your number one priority.