I'm looking for some informed opinion about the necessity of warming the engine before changing the oil, which I've been doing for the past 30 yrs. I have 3 low mileage vehicles to change every 4 mos. with dino since they are used 90% of the time for short trips. I could probably save about 25% of the time involved if I didn't drive each one first to bring it up to operating temp which I doubt the dealer shops bother to do. I will probably not reach 100K miles on any of them but would like to be able to sell them or pass them along to relatives knowing that the engines don't have excessive wear. Thanks.