There's more to a windshield wiper than just the wiper blades. There's a motor, gears, linkages, blades, and the control inside the vehicle. Newer vehicles might also have "rain sensing" wipers, which include more components than a traditional setup. Of course, Southeast Auto Service has the wiper blades for your vehicle when you need to replace them.

Wiper blades are like squeegees. The arms of the wiper drag a thin rubber strip across the windshield to clear away the water. When the blade is new, the rubber is clean and has no nicks or cracks. It wipes the water away without leaving streaks. When the wiper blades age, nicks or cracks form, road grime builds up on the edge and it doesn't make as tight a seal against the window, so it leaves streaks.

Note: Sometimes you can get a little extra life out of your wiper blade by wiping the edge with a cloth soaked in window cleaner until no more dirt comes off the blade.