I use an 18 count egg tray actually. I hate having 2 cartons kicking around the fridge so 18 means you can buy a dozen when there are still some hanging around from the last batch.
The real story: Unusually, we bought 2 dozen from the Old Strathcona farmers market. 18 went into the tray, 6 left over in the remaining carton. This lead to a marital conflict over the best way to handle the egg distribution.
