Eggs are a staple in most kitchens. I use dozens of eggs a week especially for my baking business and there is nothing worse than cracking an egg and its nasty and rotten or you need egg yolks only and the old egg yolk mixes with the white and its of no use for that recipe. Eggs are also notorious for making people sick if bad eggs are combined with improper cooking ...Imagine making runny poached eggs with less than fresh eggs?
Checking if your eggs are still usable is super easy.
Get a deep bowl and fill with cold water. Put your eggs in the bowl. Any eggs that sink to the bottom are fresh. Any eggs that rise to the top are bad and should be discarded. Any eggs that sink to the bottom but move around and try to sit on the point are in between. They can still be used for scrambling or added to recipes but not for any recipes that call for intact yolks.
That's how easy it is.