I looked up the USDA rules once...
An egg producer has 30 days to get an egg to the store. It's usually done within 15, but they have up to 30.
Eggs can be sold as fresh up to 60 days after they were laid. The sooner the producer gets the eggs to the store, the longer they can be kept on sale. But, the sell-by date cannot exceed 45 days.
Once you buy the eggs, you can then keep them in your fridge for another 30 days.
A commercial egg carton is stamped with a number representing the day of the year the eggs were packed into it (1-366). It's also stamped with the sell-by date. I'm looking at a carton I just pulled off the stack that says "322", which is Nov 18, and "Dec 16".
As for your own eggs, a hen will lay eggs until she feels she has enough. This can be a week or more. She doesn't keep them in a fridge all that time. The embryos in the eggs just sit around doing nothing, waiting. Once she starts to sit on them, the temperature goes up to about 100 degrees and the embryo starts to develop. It will take a few days of incubating to see something happening in the egg.
So, my practice is to collect eggs once a day. We've only had chooks a year now, so we haven't missed any eggs yet. If we were to find a missed egg, I would crack it in a mug and check it out. If it seemed fine, I wouldn't have any problem cooking and eating it.
