When I started looking at it, almost everything we use today is a convenience food of sorts, if you define that as a food that is already premade or pre-prepared. Are all canned foods convenience foods? I certainly use my share of canned tomatoes, canned beans, and even pasta sauce on occasion. While I love homemade bread, I don't bake for everyday use. So, if you consider processed foods as convenience foods, I don't use that many, but if you count pre-prepared foods, they are staples in my pantry and freezer, and they are the building blocks I use to play with food.
What convenience foods could you not live without? I think that you may find drawing that line a little more difficult than you imagined.