To help eggs stay usable for as long as five weeks, store them in the refrigerator; they deteriorate quickly at room temperature.
Eggshells are porous, so off-flavors and odors can develop inside the egg. Keep eggs in their cartons, stored at the bottom of the refrigerator - not in the door. The wide end of the egg contains the air bubble, so store eggs with this large end up.If you lose track of how elderly your egg supply is, test for freshness: Lower an egg into a bowl of cold water. A fresh egg will sink, ending up on its side. As egg contents shrink with age, the air bubble at the wide end expands. Therefore, an egg that is more buoyant in water (standing upright or semi-floating) is not very fresh. Use less-than-fresh eggs as a binder in meatloaf, for example.
About the only reason not to want really fresh eggs is for hard-cooking. Week-old eggs are much easier to peel.