Can someone give an example other then eggs of something that is definitely davar shebiminyan?
I can hear a svara that eggs are not davar shebiminyan because the fact that they are sold in dozens rather than pounds is for convenience sake. Eggs are fragile and therefore need to be sold in special containers that are shaped specially for them and these containers happen to have 12 slots (or 30 etc.). So when you buy “a dozen” eggs you can say a svara that it is as if you are buying a pound. (The fact that Europe switched to selling by the pound might over turn this svara though)