Once they're refrigerated, you have to keep eggs refrigerated
It's true that keeping eggs in the fridge is a weird American quirk. Plenty of countries sell their eggs unrefrigerated and keep them out on the counter, rather than tucked away in a refrigerated egg tray. And if the eggs have never been refrigerated, they can hang out on the counter, or in another cool place, for about a week. But once refrigerated, eggs have to stay refrigerated. One they're in the fridge eggs can last four to five weeks after their packaging date, as long as you know how to store your eggs properly. But how long do eggs last outside of the fridge if they've been previously refrigerated?
The rule of thumb? You can leave eggs on the counter about two hours at room temperature or one hour if the temperature is 90 degrees or hotter before you start to worry, per the Egg Safety Center. After two hours, you'd be safer to throw those eggs out and get a fresh dozen rather than chance it. Why? Because the temperature change can facilitate bacteria growth, and eggs are particularly susceptible to one particularly nasty bacteria that you've surely heard of before: Salmonella. Symptoms of Salmonella are not at all pleasant—they develop anywhere from 12 hours to 72 hours after infection and may include diarrhea, fever, abdominal cramps, and vomiting. In some people the diarrhea may be severe enough to require hospitalization. The FDA estimates that there are about 79,000 cases of illness and 30 deaths per year caused by eggs contaminated with Salmonella. So you can see why taking a chance on those eggs you left on the countertop overnight isn't worth it.
Luckily, the ways that you can handle and cook eggs properly are pretty easy. Make sure that you keep those eggs refrigerated below 40 degrees Fahrenheit, discard any eggs that are cracked, and make sure to wash your hands an utensils that come in contact with raw eggs. And then you can enjoy your delicious breakfast taco in peace.