Ever notice that once in a while, your windshield wipers will move or jump when you remove your key from the ignition? When I first got the car it used to fascinate me. It did it at seemingly random times. Later I found out that the movement was intentional. The purpose of the wiper movement is to flip the blade over to another side. It helps keep the rubber blade from permanently deforming in one position. At over 100,000 miles, I’m still on my original front wiper blades and they still work rather well. The nice California winters probably help.