says is "Depending on weather and atmospheric conditions, varying road surfaces, individual driving habits and vehicle usage, additional or more frequent maintenance may be required." This is from the on-line manual, and other year manuals may have similar statements somewhere in the schedules. I have not seen one with a specific milage given for this service, and I've looked for it. The above paragraph is the only thing I can find in the factory service manual that might suggest changing the belts after a certain period of time.