I've been getting this question a lot as I start to sell eggs.
First, if you want to keep eggs for brooding or incubating, you'll need to get incubation started within 7 to 10 days max. Do not refrigerate.
If you are talking for eating, then eggs have very long shelf life. I tell my customers the eggs are "fresh" for a month. After that they are still quite good, but they will start to sort of dehydrate. The yolks and whites will lose firmness. If placed in a bowl of water, fresh eggs tend to sink due to density and old eggs tend to float as they've lost water and gained air.
I believe I've read that egg factories date their cartons around 40 days from when they were laid or processed, but even after that required dating, most eggs are still perfectly usable.
Somewhere on the Internet is an article about the edible life of an egg for a year, and the tests they did on best means of preservation.
Most recommend refrigerating your food eggs and require it for those who sell their eggs. But they do keep fine on the kitchen counter too.
