But now that I live in Georgia, I don't think it's quite as neccesary! The oil isn't "hard" in the crankcase down here, I noticed. But being a bit of a gear head, I understand how most of your engine wear is due to starting your car, as the oil is all in the bottom of the pan, and not all through the engine. Consequently, if you start to drive as soon as you start your car, you are putting even more load on a not so well oiled machine. So I don't let my car warm up for 15 - 20 minutes anymore...More like 15 - 20 seconds. Regardless of outside ambient temperature. Plus it gives me time to play with stuff in my Element, like the radio, the power windows, the little kids in the back...Etc.