Most wiper blade manufacturers recommend replacing wiper blades twice a year because the rubber from which they are made begins to deteriorate once they are exposed to the elements.
This deterioration will keep your wiper blades from doing their job – maintaining windshield visibility and keeping your windshield clean and streak-free.
You should inspect the condition of your wiper blades often by visually checking the condition of the rubber that contacts the window. Look for wear, cracking, or brittleness. You should also turn your wipers on and apply washer fluid. If your blades need replacing they will spread the washer fluid across the windshield and not remove it.