Survivalism is a movement of individuals or groups (called survivalists or preppers) who actively prepare for emergencies, including possible disruptions in social or political order, on scales from local to international. Survivalism also encompasses preparation for personal emergencies, such as job loss or being stranded in the wild or under adverse weather conditions. The emphasis is on self-reliance, stockpiling supplies, and gaining survival knowledge and skills. Survivalists often acquire emergency medical and self-defense training, stockpile food and water, prepare to become self-sufficient, and build structures such as survival retreats or underground shelters that may help them survive a catastrophe.
Survival kits, in a variety of sizes, contain supplies and tools to provide a survivor with basic shelter against the elements, help him or her to keep warm, meet basic health and first aid needs, provide food and water, signal to rescuers, and assist in finding the way back to help. Supplies in a survival kit normally contain a knife (often a Swiss army knife or a multi-tool), matches, tinder, first aid kit, bandana, fish hooks, sewing kit, and a flashlight.
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.
The communications equipment may include a multi-band receiver/scanner, a citizens band (CB) radio, portable "walkie-talkies" with rechargeable batteries, and a portable battery-powered television. The power supplies may include a diesel or gasoline generator with a one-month fuel supply, an auto battery and charger, extension cord, flashlights, rechargeable batteries (with recharger), an electric multi meter, and a test light. Defense items include a revolver, semi-automatic pistol, rifle, shotgun, ammunition, mace or pepper spray, and a large knife such as a KA-BAR or a bowie knife.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!