There are number of realistic ideas about the end of the world; nuclear blast, warfare, fire, volcano, tsunami, hurricane or earthquake, robot uprising.
You need to have a plan. You need to get used to making things, because you won't be able to go down to the corner store and buy a biege box any more.
It's really important to buy beer and condoms, disaster preparedness can get really boring in hour seventeen... but don't buy beer, buy pop tarts
Bre is arguing that it's really important for survival to have a community and that everyone should start or join their local hacker space. Communication is also really important, get your ham radio license.
But most of all you need to know how to make things, and getting into the habit of learning how things work, attempting to fix things that are broken and making things from scratch.
Post-apocalypse currency, gold are more likely t maintain value than the US dollar, you can't get to safe deposit boxes, so bury it in your back yard. But it won't hurt to carry a thousand dollars in your wallet. If your airlifted out a disaster, your in a better situation that you would be otherwise.
You have tools handy, right?