The front end analysis of your situation should start with a threat analysis. A useful guide for both determining the threat and assessing your needs is the
Rule of Threes (3s):
You can survive for 3 seconds without ammunition, 3 minutes without air, 3 days without water, and three weeks without food.
These are, of course, generalities; but, they do help establish priorities for survival planning. In a first world country, it's best to apply the Rule of 3s to each of 3 different scenarios: at home, evacuations by vehicle and by foot. Make your survival plan modular.
3 seconds without ammo addresses human confrontation:
If looting is a factor, a firearm may be appropriate. It's easy to store at home and to transport by vehicle; but, would it make the weight cut if you had to carry it for any significant distance by foot? Would your budget allow for multiple firearms, one for each scenario (e.g. shotgun at home, rifle in the vehicle, and handgun in the backpack)? Are you knowledgeable enough about the use and transportation of firearms so that possessing one doesn't work against you with relief agencies (incl. law enforcement when it becomes available)?
3 minutes without air has multiple contexts:
In a WMD environment, it means having a gas mask. Where there is a high risk for conventional injury, it means knowing CPR and having an Ambu bag handy. In a waterborne environment, it means having life vests. While people can survive for more than 3 minutes without oxygen, most people have only up to 3 minutes of useful consciousness without breathable air.
3 days without water pertains to static survival:
There are ways to safely store large quantities of potable water at home and 5 gallon water containers are easily transported by vehicle [that's what many militaries use]. Carrying water by foot; however, is another story. Water is heavy and bulky. This is where backpackable water purification devices come in. Whether it's by filtration, chemistry; or, a combination of the two, the ability to purify available water is essential when moving by foot. Backpackable water purifiers have their limitations. They remove harmful biologicals; but, not harmful chemicals and they do not desalinate seawater.
3 weeks without food; also, pertains to static survival.
Stocking up at home is easy and mostly a matter of rotating supplies for economy. Avoid storing food in vehicles in temperate or warmer zones; rather, have bundles at home ready to go. Choose ready to eat foods for most circumstances including backpacking. Carry dehydrated foods only if potable water is assured.
THE AFOREMENTIONED constitutes a gross overview on establishing priorities for a survival situation. All of the rules may not be applicable to all situations: it's the thought process that counts. Applying the Rule of 3s is always a work in progress. The threat may change, there may be new solutions; or, new products for better implementing old solutions. An adjunct to the Rule of 3s is
shelter. The requirement for shelter is highly variable. Beyond the Rule of 3s, there are other specialized (e.g. medical, electrical, communications) items that can enhance the chances of survival and the quality of life in a survival situation. They're not much good if you're dead (or going to die anyway); because, you didn't first take care of the basics.
The US government has sent me through several survival courses (e.g. temperate zone, desert, NBC). If I actually gave you a list of my personal survival gear, it might scare you off the subject (it could cost several months pay and it might not be right for your situation anyway). I will, however, answer specific questions to the best of my ability. To paraphrase an old saying: 'Give a man a checklist and you prepare him for a day, teach a man to make a checklist and you prepare him for a lifetime.
