Most recipes are very lax in their quantities. The size of an egg doesn't usually make much difference, at least for the cooking and baking I do.
For the most part, they are a mixture of sizes including both large and small, so it usually evens out. They are rejects primarily because of shape (can't be packaged in standard containers, too long and they would break when the lid was closed; too small and they would move around and crack) or because they have double yolks (purely cosmetic). The cosmetic look was a bit offputting at first--we are all used to the expected appearance with a single yolk--but it makes zero difference to the taste.
Cooking ≠ baking. For baking small changes in relative quantities can actually make a huge difference — maybe not for your simple cake batter but definitely for more elaborate bakes, and even relatively simple standards such as brioche dough. It won’t ruin the result but it will change the outcome.
For the most part, they are a mixture of sizes including both large and small, so it usually evens out. They are rejects primarily because of shape (can't be packaged in standard containers, too long and they would break when the lid was closed; too small and they would move around and crack) or because they have double yolks (purely cosmetic). The cosmetic look was a bit offputting at first--we are all used to the expected appearance with a single yolk--but it makes zero difference to the taste.