It's easy to go overboard and make silly choices, but it's also easy to plan a good contingency. I keep 1 year of dried food and 3 months of canned / jarred / frozen food. Any more than that and it gets wasteful for me. I have backup grid-independent solar power, and I also keep a small veggie garden going most of the year.

I like to re-pack my dried foods into emptied, washed, and dried PET bottles, because they store better. I use 1L Waterford's bottles because their shape is perfect for maximizing storage and stack ability. I repack large bags of dried food into these with oxygen absorbers, and packed this way, rice, lentils, wheat berries, and barley will last 20 years. Rolled oats will last a couple years. Sugar and salt will last indefinitely. Scaling them down to 1L individual volumes means you can crack one without introducing contaminants to the others

Keeping a rigid system of labelling, inspecting and rotating your goods is as important as having them in the firstvplace