Are you training for a climb that will involve hiking on dry trails to your ice climbing location? If so, it's probably good to try the boots out on a dry trail at least once before your trip. Otherwise, I'm not sure there's much reason to be trying to break them in. From what I've experienced (limited -- old Koflach plastic boots) and heard from other climbers with newer boots, most "ice climbing" boots don't really break in over time. They fit about the same the 20th time you wear them as they did the 1st time.