Reading labels helps you buy products for their intended use. If you're making soup, you don't need to buy whole fancy tomatoes. You can buy a less expensive kind because appearance won't be important. Reading labels helps you buy products that fit your budget and the amount needed for your family. Even though a large size may cost less per ounce, it won't be a bargain unless you use all of it.
Ingredient order is important.
Reading labels lets you know what ingredients you're actually paying for in the package. The first ingredient listed is the one which occurs in the greatest amount. Be careful about products listing water as the first ingredient. Reading labels helps you know how much convenience you're buying. Some pre-packaged dinners can be heated and served.