"Half a dozen of one, 6 of the other"
A half dozen = 6, so what does this idiom mean? When a person says this, he is telling you that what you just said is redundant or that the distinction you were trying to make isn't significant. Example:
"Honey, should I order two small pizzas, or 1 large?"
"Half a dozen of one, 6 of the other" means he does not care since its the same amount of pizza.