Depending on how they're stored, eggs can survive anywhere from a few weeks to a year. But you wouldn't eat an egg based just on faith, would you?
Eating a rotten egg can cause food poisoning that can last a few days or land you in the hospital for a lengthy stay. So, how can you know if an egg is edible?
The scent and color of eggs are two of the most apparent indicators of freshness, so if something is odd, it's best to avoid using them.
Eggs will keep fresh in the refrigerator for around 3 to 5 weeks. The "Sell-By" date on the box may have passed, but the eggs are still totally fine to use.
If you're still unclear or don't have packaging, a water test can be used to determine the freshness of your eggs.
Place the egg in a glass of water; if it descends and lands on its side, the egg is fresh.
If the egg is upright but lies at the bottom of the vessel, it is older but should still be edible.
If the egg floats, it's probable that it's not fresh, and you should avoid using it.
The egg's exterior is semi-permeable, allowing oxygen to enter over time. The egg will gradually float as its air content increases, signifying its age.