The point here is that by the time I've scraped the car (about 2 minutes) the heater is blowing warm enough for my breath not to mist up the windscreen.
My other point being not many people actually keep a new car long enough for it to need an engine rebuild, so a small amount of additional engine wear will have no effect. If it comes to that how many cars actually reach a stage where an engine rebuild is needed, most are scrapped long before that point. My Triumph has just gone over 161,000 miles and is yet to have an engine rebuild (I have had two replacement cylinder heads though)...