I think that the number of ice creams to get is the best thing to pre-decide. I'm looking at you, Ben & Jerry's. (We usually let the coupon limit decide how many we are getting, and don't usually get the small-carton expensive brands outside of sales.) If we were determined to Try All The Flavors, we'd have to rotate through them at a slower rate. For me, the "we're getting chocolate, who cares about The New Shiny" gets defeated at first sight of the New Shiny, but with a 1 carton limit I would have to choose: chocolate OR New Shiny -- a narrower choice, but easier for my brain to cope with.