Many OEMs and wiper manufacturers recommend replacing the wiper blades every six to 12 months. However, wiper life can vary greatly depending on region of the country and the conditions under which the vehicle is operated. The only way to know is to inspect the blades.
Air filters, cabin air filters, oil filters and (sometimes) fuel and transmission filters are important maintenance parts that typically are replaced according to a time and/or mileage schedule.
Other than cross-referencing or measuring the occasional dirty element, we don’t have much opportunity to see the condition of the filter, an advantage that our professional customers enjoy every oil change or other service opportunity.