Because farm fresh eggs vary in availability, having enough eggs all year long can be a challenge. Most small farms cannot keep an inventory of egg layers in production year round. This suggests you stock up when there is surplus and skimp when there is a shortage. Eat with the seasons when it comes to eggs!
Most chickens will amp up their laying in response to the increased light of the springtime. Consequently, they will also decrease their laying in the autumn. That's why quiches are so popular in the spring!
If you know an egg is fresh (ask your farmer when it was likely laid) and it has its natural protective bloom intact, the egg will be fresh for many months. I once saved some eggs for a whole year, eating one periodically, and you can read about that adventure here. If ever in doubt about the freshness of an egg, simply crack it into a small bowl and check it visually before consuming it.
I don't recommend you have a giant stockpile of eggs, but it is fine to stock up a bit when there is a surplus and to put away a few dozen for winter use before production tapers off for the year.