Yep I agree with most of the points being made here. I generally warm mine up 5-10 minutes or until the temp gauge starts moving in the winter mornings and then until it idles down the starts after the first one. On single digit mornings though my RPMs will sit at 1,200 for a few solid minutes, I would never advise anyone to start putting load on an engine that doesn't want to idle down yet, it's no good to shift into gear at 1,200 and that engine is not warm enough yet to be under load as it is still running a rich mixture trying to heat up to run properly. 30 seconds minumum is a good rule of thumb until you put it into gear.