So I don't consider myself a prepper really, but our family of four usually has 1-2 months worth of food in a basement pantry that we rotate through. There is little waste as we are eating the stuff anyway and we only store things that will last. Each year for about 10 years (we've been getting lazy so haven't done it the last three years or so) we would hold an austerity month, usually in feb. because it is short. For that month we would make an attempt to buy absolutely nothing. By the end of month we would usually have purchased unleaded gasoline and a couple of items that we hadn't thought of, but those we're added to the list and stocked for the next year....except the gasoline. I own a bunch of mountain and road bikes and can ride to work if I really needed to, but Feb. is really cold where I live....so yeah I'm lazy. At any rate if everyone had at least the basics (btw https://gossner.com/uht-milk/ is awesome and I don't work for them) it may help out for any sort of emergency that requires you to be stuck at home with few outside resources.
And you don't have to waste things you buy....just get more of what you normally use minus things that go bad quickly, and rotate through it. Frozen and canned vegatables and fruit aren't as good, but they're not terrible either on occasion.