I've read about time on your feet too, and was trying to do this prior to doing my first half marathon, so I didn't mind if I didn't cover huge distances. But like Laura I only ran 10 miles leading up to the half marathon and ran The Beast - an off road 13 mile event - a fortnight before the half. I did 1:46:16 in the half and felt fine. As I have to mix running with cycling I don't get many runs in a week. So I was just hoping that doing 10's would be OK.