It depends on the type of gauze. A sterile gauze will expire after some time as the chemical keeps it sterile works until a specific time period. In such a case, it is highly recommended not to use an expired pad. You can read the backside of the package of the product to know the expiry date. However, for non-sterile gauze pads, there is no expiry. However, the pad must remain in a hygienic container. It has to be free of dirt debris and bacteria of all types. Only then it is recommended to use on any wound.