This is a page about extending the life of windshield wiper blades. Here is a simple tip that may give you a little more time, before you need to replace your wiper blades. It could certainly be helpful if you can't make it to the store right away and its raining.
Before replacing worn windshield wiper blades, try roughing up the edges of the blades with sandpaper or even an emery board. You can probably get a few more weeks of use out of them!