@taxistaxing:
calm down. I agree with Adam. I never said that you should avoid runups, I'm just questioning the reason to do it when you have already flown a bit, the engine is warm and all indications have been normal. How high do you think the probability is going to be that the run-up is going to reveal something that won't show up during the first stages of the take off run?
And by long runways, I mean in excess of 3000ft / 1000m.