I've heard it said alot thru the years that most engine wear occurs at start up. Could that be because cold oil doesn't flow as fast thru the engine, as warm to hot oil does ? I'm sure everyone on this site has seen the tests where oil comes out of a freezer in a glass tube at 20 degrees f, and is poured out and timed to see how long it takes to go about 10 inches. It doesn't move anywhere as fast as warm oil does. So that tells me your not getting alot in the way of wear protection by taking off as soon as the engine fires off. I let my old Ford Exploder idle between 2-3 minutes before I start driving. Especially in cold winter months. No clicks ,no ticks, no funny noise's, the engine has never been opened up 280k miles.,,