Methinks it helps to know if you're buying
washed eggs (don't understand why but the US washes their eggs) - washing
takes away the natural protection and makes them go bad much quicker.
Unwashed eggs (EU countries and I would assume plenty of others as well) you can keep in a cool(ish) place for 2 months easily.
Try to buy fresh, unwashed eggs that haven't been refrigerated and simply store them somewhere coolish and you're good to go for pretty much any passage
I buy supermarket eggs and keep them in a cupboard for about 8 weeks w/out issue. They'll probably keep longer then that, but they're usually gone by then
When in doubt, I put them in some water to see if they float or sink. If it sinks, eat it. If it floats at the top, toss it overboard