A good pair of mountaineering boots should have several key features to ensure they are up to the task of providing support, warmth, and traction in a variety of mountainous environments. They should be stiff to provide support and stability on steep and uneven terrain and be insulated to keep your feet warm in cold conditions. And while you want a boot that is sturdy and supportive, you don't want one that is so heavy that it weighs you down and makes it difficult to move quickly and efficiently.