To make my life easier in the kitchen, I like to keep various staples on hand. When I am on my last one of something, then I know it's time to buy another.
Some things I always try to have available:
Beans for Mexican food
I always try to keep one bag of beans that has not yet been opened, plus some beans already cooked and ready to use in zip-lock bags in the freezer.
(To cook beans, first rinse them and soak them overnight in about twice as much water as beans. Rinse them and soak them some more. When you're ready to cook them, rinse them and add fresh water. Boil gently until they are soft. Depending on the type of bean, it can take from 30 minutes to an hour. Light colored beans cook faster; black beans take longer.)
This I buy from local farmers when it's in season, as the only alternative is expensive garlic from other regions of the country or garlic from China, which I feel is not safe to eat. I peel the garlic, rinse it off, and store it in zip-lock bags in the freezer. I also keep some thinly sliced in olive oil in an air-tight mason jar in the refrigerator. Of course, I always keep some fresh garlic, unpeeled, in a bowl in a cool cupboard. (One can never have too much garlic.)
When I make a loaf, I slice what has not been used, put parchment paper between the slices, and put it in a bread bag in the freezer. When someone wants a sandwich, it just takes a few minutes to thaw 2 slices of bread. (I put them on a cooling rack to thaw.)
When I make a pan of brownies, I individually wrap what is not eaten and keep them in the freezer. You never know when you'll be needing a brownie.
Anything I missed?