I'd recommend they be collected at least once a day. I did that growing up on a farm and we never had problems with the eggs. Some people collect them more often, especially if they live where it is very hot or if they live where an egg will freeze during the winter. I think it is best to collect them in the late afternoon or evening. Eggs left in the nest overnight are an invitation to certain egg eating predators, especially rats. With all that said, I think you are asking how long before they spoil. It depends on your weather, if you have a broody hen sitting on them, or if they get wet, but they can last for a few weeks if the conditions are right. This link may help. Storing Eggs http://www.motherearthnews.com/Sust...ggs-a-Year-or-More-Without-Refrigeration.aspx
We usually collect the eggs after lunch, and when we lock them up for the night, sometimes we forget to do it after lunch, and just get them in the evening...unless its REALLY hot out, or REALLY cold, then we check more often...I would say you would at least want to do it once a day for sure...after they have all had a good chance to lay