My grandfather fought in the Leningrad siege (if you dont know about it look it up on wiki) on the Russian side. Because of that experience he told me that there two important items to have if you are going be facing any kind of disaster that lasts for longer than two months. The first one is salt. Its cheap, doesnt expire, you need it to cook, can be used to wash your teeth, and store meat and fish. The second one is soap, again cheap, doesnt expire and if you dont have access to medical help and cant wash yourself will have a higher chance of infection. Just thought I would share that since I havent seen it brought up here.