Warrior Skills Level 1 , pp. 3-93 through 3-100
FM 21-18 Foot Marches 2017,
Appendix E and F, pp. E-1 through E-11, F-1 through F-14
As the Soldier's Manual Of Common Tasks reference above notes, using basic items like sunscreen, lip balm, insect repellent, iodine water purification tablets, foot powder, hand sanitizer, soap, shampoo, toothbrush and paste, baby wipes, washcloth, towel, and toilet paper will prevent far more injuries, illnesses, and general problems than anything inside your first aid kit.
So will eye protection, hearing protection, proper protective clothing, and a hard hat/helmet.
You have no fangs, claws, scales, or hard shell. You are small, slow, soft and squishy, and easily punctured and damaged. Most of the animal kingdom is sturdier, meaner, or faster than you, and much of it is higher on the food chain.
But you have a superior mind, if you use it.
You can leverage that to make devices to dominate and thrive in any environment on the planet. Or fail to do so, not use those advantages, and rejoin the circle of life as fodder for everything from carnivores to bacteria.
The rules of soldiering, since at least Caesar's legions, are the exact same rules for everyday life, and doubly so in bad situations and tough times.
Purify any water before you drink it.
Drink enough water every day.
Cook your food thoroughly before you eat it.
Eat when you can, rest or sit when you can, and sleep when you're supposed to.
Wash your hands before you eat, with soap, or hand sanitizer.
Apply sunscreen and lip balm.
Use insect repellent.
Brush your teeth.
Wash your face, your feet, your body, and your clothes.
Change your socks and underwear daily, or more often.
Bury your waste properly, and far from food/water.
Dispose of trash adequately.
Wear appropriate protective clothing, including helmets and body armor, if its use is wise and indicated.
Wear eye protection whenever you're using your eyes (unless you figure you can grow new ones).
Protect your hearing (if you like being able to hear).
Hardass = dumbass = future (entirely preventable) casualty.
That means your water purification gear is as important as ammunition. In fact, more so.
You're going to be drinking a gallon of water/day, forever. You hopefully won't be trading lead every day, even in a war.
Your armor isn't just body armor, or a helmet. It's also sunscreen, insect repellant, and lip balm. And sunglasses, a hat, long sleeves, long pants, and sturdy boots. And clean socks and fresh underwear.
Part of the function of leadership is to ensure their subordinates are not being dumbasses.
It's called taking care of their troops.
The function of everyone else is to pro-actively do what they know they should, and take care of themselves, so other people don't have to do it later.
And then to look out for their buddies.
And finally, don't do stupid $#!^.
The things you have to do, in anything from tough times to a total breakdown of society, will be plenty hard enough for each day.
Doing anything you don't have to do under those circumstances is dumb enough.
Doing dumb things you shouldn't be doing at all is inexcusably stupid.
Don't be That Guy.
Because if you Play Stupid Games, you're gonna win Stupid Prizes.
That concludes your basic First Aid instruction, and your second day of training.