Bombs rain from the skies, alien ships descend with lasers ablaze, improbably proportioned, irradiated sea monsters tear through essential infrastructure. You'd think that running, screaming, and finding clean underwear would top the list of activities likely to improve your chances of living, followed closely by finding a sustainable food source and offering sexual favors to the person with the most impressive arsenal. Unless you were a prepper, in which case you'd be worrying more about the safety of your cigarette stockpile.
OK. Great. You've stockpiled for the end of the world, you quack. The chances of the world ending are smaller than ... holy crap, what the hell is a supervolcano? See why we're all doomed in 5 Ways The World Could End That You'd Never See Coming. And if that's not enough to get you to build your own bunker, check out 6 Tiny Mistakes That Almost Ended The World. Really, the planet almost ended due to a blown fuse? Come on humanity, let's get it together.
Here are just a few choice gems from The Prepper Journal's 11 Ways A Condom Can Save Your Life: starting fires (they're great at protecting tinder from moisture), hunting for food (sexiest slingshot ever!), and transporting up to two liters of water (yes, rule 34 applies; no, we won't provide the link). They also make serviceable stand-ins for rubber gloves and can be used to protect the muzzle of your other essential survival tool (killing it right now).
Monetary disaster investors believe the Federal Reserve system is fundamentally flawed. Newsletters suggest hard assets of gold and silver bullion, coins, and other precious-metal-oriented investments such as mining shares. Survivalists prepare for paper money to become worthless through hyperinflation. As of late 2009 this is a popular scenario. Many will stockpile bullion in preparation for a market crash that would destroy the value of global currencies.
I'm not quite crazy enough to say that epinephrine will help you survive the inevitable zombie apocalypse (you can go here for that). I'm just suggesting in a roundabout way that if you happened to be in a situation where something was trying to eat you, the increased heart rate and blood flow to your muscles brought on by a well-timed dose might just save your life.
For global catastrophic risks the costs of food storage become impractical for most of the population  and for some such catastrophes conventional agriculture would not function due to the loss of a large fraction of sunlight (e.g. during nuclear winter or a supervolcano). In such situations, alternative food is necessary, which is converting natural gas and wood fiber to human edible food.
I am guessing, I am the homesteader. Or, I would call it “shelter in place prepper”. Since, I am in advanced age, I don’t have the mobility of a 20 year old, to bug out. The problem, I see with a homesteader, is if you don’t have the arms and man power to defend what you, then it will all be taken away. Reason, I am into hiding food in plain site. Pecan trees, oak trees, black berry patch, mushrooms, and such.
Every year in the US about 150 people die while out and about in national parks, more than 1,000 die in hunting-related incidents and thousands of backcountry enthusiasts get in deep trouble and require a Search and Rescue team to save them; with dozens of those folks dying while awaiting rescue. Most fatalities are the result of poor preparation. Bad weather descends and people get lost. They wander without water or shelter, often injuring themselves in the process. If they survive they often suffer frostbite, hypothermia, dehydration, trench foot or some combination of them all.