If raw fresh eggs are kept in the fridge they will maintain their best quality for 3-5 weeks although backyard eggs don't last more than 3 days in my fridge because they are usually gobbled up or used in baking.
If you are questioning whether the eggs are 'good' or not, you can try the float test. As an egg ages it's air sack develops. As a result you can check if an egg if safe to eat by dropping them into a bowl of water. Good eggs sink, bad eggs float.
I keep our eggs on the counter. After I collect them, I rub mineral oil over them, and the put them in cartons. I believe the US is one of the only countries that refrigerates eggs. Nobody has gotten sick yet.
I don't refrigerate. I keep my eggs on the counter top and I've eaten them as much as 2 months old when I've had a real glut without any treatment, so I imagine they would probably keep 3 months in the fridge.
If you have had some a while and you are concerned about them, crack them into a separate bowl and if they look and smell alright, then they are fit to eat in my opinion.