The break-in process for combat shoes can take a few weeks. Begin with wearing your boots for short periods. Start by wearing very thick socks so that the boots' leather warms up and stretches to mold the shape of your feet. Sometimes, applying a leather conditioner can also help soften the materials. If you want to break in quickly, use a hairdryer to warm up the leather. However, be careful as hot air can sometimes damage the leather. Use the lowest hairdryer settings to blow the air, then bend and flex. Take help from a cobbler if necessary.