What you think will happen, makes a difference in what you need. If you are anticipating an 'end of the world' scenerio, such as that killer comet hitting Earth and killing 95% of all life, human and otherwise, then if can get past the first few years, you might be able to survive at cave man status.
If what you are preparing for is a local disturbance, then your needs are vastly different.
You really do need to have something in mind when you prepare.