My car lives in a garage, so by the time I start it, then idle out of the garage, then press the remote button and make sure the door is closing, then idle down the rest of the driveway, its as warm as it needs to be.
But short answer no I dont, with all the cars I had, and no major problems caused. I only ever warmed my cortina up, as it sat outside, and was friggen freezin in winter, was only to warm the heater up :0)
I did put something here, but it vanshied, I think
"So long and thanks for all the fish!"