As far as how long you would have to plan for and how deep the preps need to be, that depends in a long term situation more on the person and plans (includeing knowledge) than on the situation and how society resolves its self. If you plan to live strictly off of what you have put away before hand untill civilization (basicly) as we know it returns then you better have a nice huge warehouse and a few barrels full of $100 bills to stock up. If you plan to suplement it by hunting/gathering then you can improve it some though the pickings are likely to be a bit slim. If you supplement it by raising animals and a garden (possible even on VERY small plots, like an acre or so) then your need for the food supply goes down a WHOLE lot. Even if this is the plan but not in action and being used for full support before hand then you would still need 6 months to 2 years supply of food as well as seed and begining livestock or items to barter for them at a premium value. I say 6 months to 2 years since if something happens now you wont be eating from a garden untill the earliest stuff in say May or June and mostly along in late July. Animals tyake a while to produce offspring and for it to grow to a size to be eaten also. Then figure that with Murphey involved the first year out of the gate may be a drought, if you havent already been doing it you will be on the learning curve and so on. So regardless ANYTHING you have beyond todays food set aside puts you ahead of the game and from there its just how far you can or feel you need to go. My ideal situation wouldbe to have enouph set aside to feed the whole family off just stores for 1 year. I figure with others who would likely show up and be to great of assets to turn away bringing its use to shorter time and suplementing it with hunting/gathering AND farming and raising meat that that would go for around 8 to 18 months depending on the situation and would give a REAL big saftey net of time to get into the new swing of things since I already do some of it now, but thats just my own thoughts on it.......and seems to have strayed quite a bit from the main thread. Oops.