Ahh, the UV filter. It is probably the cheapest filter available for your lenses and, quite frankly, doesn’t have that much of effect on modern day digital sensors (though it still has significant impact on film and cheaper sensors). With that in mind, why is it that I constantly recommend the use of UV filters? Piece of mind: It protects your lens, which sometimes costs more than your camera body. But this is far from a new tip. My mentor passed this wisdom on to me. And many of my fellow photographers have had the tip passed on to them from their mentor as well.
But in this day of self-taught photography, you read blogs like mine and like Beyond Photo Tips (an excellent blog). But since Ms. Mr. Chandradhas beat me to the post, I’m not going to completely reiterate everything she says. I suggest you go read the original article: Tiny Tips 16: Always Use a UV Filter