what kills these servos is vibration and excessive gear train load from poor choice of mechanical advantage [ too much control surface travel for the application]. It takes much less travel to get the job done than you might think, too much travel built into the control throws reduces leverage at the servo and puts more strain on the gear teeth. It also contributes to a "jumpy" model and more battery drain. The inner hole or middle hole on the servo arm and about 3/4"-1" up on the control horn will give enough control surface movement to control any small model that is balanced right.