Idling an engine is pretty useless. Sure, it warms up some of the oil, but the uncirculated stuff is still sitting cold at the bottom. The gearbox, differential and everything else is also still stone cold. I normally turn the key, let the fuel pump prime, then turn the key. I'll then get some music up and sort myself out. In winter I let the revs drop, in the summer I tend to give it fifteen seconds or so and then slowly make my way out of the garage in reverse. By the time I've come out, shut the door and put the fob away, it's usually dropped below the cold start idle. In the winter I will let the engine revs drop before moving, or turning on the heating. That said, I also don't really use the throttle or go above 15mph until I get to the end of the road anyway. I don't really believe in letting the car warm up while stationary - things need to be moving and under some load IMHO. Modern engines don't need warming up in the traditional sense. As long as they're driven gently until they're warm, they'll be fine. Oil temperature is another story however - I won't put my foot down until I'm above 90 degrees. A GPF will regen during overruns. That means if you put your foot down on a slip road and are in third gear at 70mph, the car will hold that gear (and thus the revs and exhaust temp) for a few seconds, before shifting up. The car won't regen anywhere near the key being turned.