I was merely specualting as this is entirely subjective and I've not run a marathon yet, however it's very interesting to read people's experiences on the matter.
My perspective on this was that running a 6:53 or faster over 26.2 miles puts a far greater level of stress on your body than a minute slower over a shorter distance. Surely you need to prepare your body for that in some way, although perhaps I'm underestimating the negative effects of doing full distance in training.
People alway say you don't need to run 26.2 miles to do a marathon, which I believe to be true.
If you're training to run a certain time, I think there's a lot to be said for having run the distance perviously. However, has anyone here run sub 3 hours the first time they've run a marathon, be it in training, competition or whatever?
It's a fast time, but I think that to run that fast over 26.2 miles, 99.9% of people need to have run marathon distance previously.