We highly recommend that you change both springs at the same time since both springs have been under the same amount of stress each time the door has been opened and closed. Unfortunately, a visual inspection of the spring can not determine the further life expectancy of the spring. In many cases, it will cost less to have both springs changed at the same time than if you only had one spring changed at a time. In addition, if you have extension springs on your door, the door may not balance properly with one new spring and one fatigued spring. Place a service order today to have both springs replaced and get your door back in proper working order!