Periodically the sweatband needs to be replaced, as it becomes saturated with oils and perspiration and can no longer protect the hat. Your sweatband will usually last 1 - 3 years, depending on how often you wear the hat and in what climate. Flip the front of the sweatband out to check for saturation regularly after 6 - 8 months. Perspiration, over time, not only stains the hat but breaks down its natural fibers. This is the other critical thing besides proper handling and storage for maintaining the life of any good hat.