It depends on your circumstances. When I lived in rural upstate NY, I would have a large stockpile of all manner of items. Basically, you needed to be ready in case you were housebound for a couple weeks. Now, we live in coastal NC--hurricane country. I still need to have emergency supplies for a week or so, plus I have more (and larger) children these days. OTOH, I also have 3 grocery stores within a mile, plus lots of other shopping venues, so I'm much less likely to be housebound--the kids literally walk to Publix for "emergency" supplies, like s'mores fixins.
I always try to keep a spare gallon of milk in the back fridge, and a loaf of bread in the back freezer (in the garage). That's mostly so we don't have to make emergency runs at 6am because we're out of one or the other. I keep a good stash of ingredients in my pantry, but that's more because I don't think from day to day, what I'm going to cook for dinner.