I did my first marathon in March and ended up with black toenails, 4 of them and 2 nails subsequently dropped off. Being a newbie i didn't know about the half size bigger thing, so i immediately bought new shoes half a size bigger and yesterday did my next marathon on a hot day. The last 5 miles were painful in the toes. I have those funny 'Roman' toes where the second toe is longer than the first and they were really painful and made the race in the last 5 miles miserable.
What can i do about this, should i go up a whole size? if i do that will my feet move around and then run the risk of blisters - which so far i have avoided.