I can honestly say i have never needed to sharpen in the field. One simply switches to another knife if the edge ever dulls (extremely rare for me). After all i normally have between 5 - 10 knives on my anyways.
heck on the last BC fatwood hike i had 7 , and that covered a few hours of fatwooding
heck on the last BC fatwood hike i had 7 , and that covered a few hours of fatwooding