Alright, I need some advice here. I have been wearing Kenetrek Mtn Extreme 400s for 4 years now. The first year I got a blister on my left foot after 5 days of hunting, brought them back to Scheels and they replaced them immediately. Since then I've had the same pair. I take care of them, I wear liner socks and this year ended up getting a huge blister on both heels during a 9 day elk hunt in Montana during early bow season. Anyone who was out there this year knows it was brutal (dry, hot, etc.). My feet were sweating like crazy and I developed the blisters after about day 3 or 4. I'm wondering is it the boots (the shape of the heel cup), my feet or is it the sweat causing all the friction between my heal and the back of the boot through the socks? They are excellent quality and when I started to blister during the 2010 season, the liner socks solved the problem. Now, I'm not so sure. There are a million options out there and Lowa just put a new boot this year, the Ticam GTX that looks really promising. Any help would be appreciated.