There are lots of great egg tips in What's a Cook to Do? but none better than How to Store and Use Older Eggs:
Eggs keep for weeks in the refrigerator, and while it takes them a very long time to actually go bad, there are times when it helps to be able to to tell an older egg from a very fresh egg. (Some recipes won't work if the eggs aren't fresh.)
1. An older egg will slosh around when you shake it because some of the liquid it contains will have evaporated and create a large air pocket.
2. Older eggs don't hold together, so that when poaching, for example, the white turns into an amorphous, unpleasant foam.
3. When hard-boiling eggs, use an egg that's a little old because it will be easier to peel.
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