For me, this one is easy, as you simply have to ask yourself the question: Do you ever, in an evening, consume only one 12 oz beer? Or split one 12 oz beer with others? I try and bottle in 22oz bombers, half-liter bottles, and even have 20 one-liter (34 oz) flip-tops. I find the fewer bottles, the faster bottling, and of course less cleaning and sanitizing and fewer labels to make if you are into that kind of thing. Go Big!