InDebtForAudi<3

It almost winter and I leave my car outdoors so its going to be ice cold whenever I want to drive it this upcoming season. Usually when I start up my S4 I let it idle till it sits at 800rpm before I start driving. Other sources say you should leave it running for ~5 mins before driving, some agree with me, and some say not to leave it running for too long cause its not good for the car. I was wondering what you guys think and how long I should keep my S4 running before I start driving it especially when the temperature reaches freezing?

Thanks.