If your boots are more than about a year old, replacing them will make hiking more comfortable, thus more fun. Understanding the parts of a hiking boot can help you make a good decision on which is best for you. From the bottom, the outsole is nearly always made of rubber. The main feature of the outsole is the lugs, designed to give the wearer traction in less than optimum walking conditions. The internal support of a hiking boot is also important. Shanks are placed between the outsole and insole for load-bearing stiffness and support. The midsole is what provides cushioning and makes a boot comfortable to wear on long hikes or backpacking trips. Many midsoles are made of ethyl vinyl acetate (EVA) of varying densities. Lastly, a hiking boot’s upper is where you’ll see the most difference. These range from synthetics like polyester and nylon, to nubuck leather, to split- and full-grain leather, along with combinations of those materials.