I put my studded Nokians on early enough so not to encounter black ice unprepared. Generally for me in Maine its around thanksgiving weekend each year. If they are carbide studs, no problem running them on dry pavement as the carbide does not wear out. They will last the lifetime of the tire itself, generally 3 to 6 seasons depending on the mileage. This way I only have to change the tires out twice a year and the only drawback is studded tires are slower and you'll get tired quicker so pace yourself and allow more time for your trip.