If you store your baking supplies (flour, sugar, etc.) in opaque containers, use this trick to see how much you have left without opening the container. Instead place a rubber band or a piece of ribbon or a magnet (for stainless steel containers) on the outside of the canister at the supply level. Next time you use it, move the band to the new level. You’ll be able to keep an eye on it, and know when to add the ingredient to your grocery list.