Your Chisos boots will last decades with appropriate attention. The vamp (leather surrounding the foot) and leather shaft require only minimal care. Condition this leather about once every three months. Store in a cool, dry location and take a day off between heavy uses to allow the insides to properly dry.
The leather soles of your boots are designed to wear out and be replaced, much like the brakes on a vehicle. Your mileage will vary depending on conditions of use, your weight, and walking style. Avoid repeated exposure to water and excess moisture.
To extend the life of new soles, have a cobbler apply a rubber sole saver upon receipt. When needed, a cobbler can perform a full resole and heel replacement.