I knew a wise gentleman (who has since passed away) who was a licensed mechanic and manager of a large fleet of cars, trucks and construction equipment. He always said that a cold winter start could take 5,000 miles off the life of an engine due to poor lubrication. I don't know if that is true, especially with today's improved motor oils. However, some sort of engine pre-heat can't hurt. Some of my engines need it to start, others don't, but all are equipped with block heaters or in-line heaters and they are plugged in prior to winter starts. I think it is good insurance.