Hi all, I have the impression that as I unfold/fold the boards before and after sessions of play, it'll eventually start to wear out on the fold mark in the middle of board. My "Heroes of Normandy" is brand new and I can already see on some boards tiny dots of white on the middle fold mark. Is it better to store them flat, but then I cannot store them in the box (kinda wish the box was a tiny bit longer)? Also, I've heard some people play with the boards under a plexiglass. Is it worth it to protect the board? Many thanks in advance.