Being prepared with food for a year could be pretty easy to do without buying those 25 year barrels or buckets that are advertised, with canned goods. Most canned stuff is good for more than a year, so once one had enough to last a year stored somewhere in the house, the cans could be used before expiring and replaced with new cans, and one could continue like that forever and still always have a full years' food supply, fresh and ready if needed.
It's true, but I actually linked to a calculator. I have found that calculator helpful to figure out how much food my family might need for an entire year. Also, some things are better stored in buckets (grain, for example).