Here we are into December and cold weather. There are the Die-hards that brave the the winter elements and the Hibernators that put away the airplane till spring. If you are a Hibernator it is a good practice to change engine oil. Old oil has picked up the containments that can cause corrosion over the winter months and with new oil you avoid that problem and have one less thing to worry about in the spring. If you are real serious about winterizing you might consider desiccant plugs in the top sparkplug holes.
    Die-hards and have a heated hanger bravo to you. For the ones that do not have that luxury and have to deal with an un-heated hanger and a cold engine preheating may be required. Cold thick oil may not get to main and rod bearings or lifters for proper lubrication. Worst case if a insert seizes or slips in it's position it could plug the oil feed passage to the main and rod bearings down-stream of the flow. An insolated blanket over the top of the engine cowling helps to hold in the heat  generated by preheating.