I generally only have mine running for about 30 seconds or upto a minute, anymore than that is a waste of petrol and time.
Like the other guys said - go easy for the first 5-10 mins of driving but wouldnt personally sit there stationary for that long.
I use my Oil Temp [factory on 34] gauge to work out when I can drive a bit harder If the oil temp is cold, you dont wanna drive hard.
Also use your last 5-10mins of driving to cool the car down after a fang, then you only need a short amount of turbo-timer - again I use my Oil temp guage to workout whats needed.
Sorry got a bit carried away, hope all this helps