I received an e-mail asking me about UV filters on lenses. The question was "Do I need a UV filter on the end of my lens to protect it?". There are two schools of thought here and it really comes down to personal preference.
School of thought 1: Put a UV filter on the end of all your lenses and leave them there. This will protect your investment from being scratched. -This is a great accessory selling technique for camera shops.
School of thought 2: You paid hundreds if not thousands of dollars for top quality glass. Why would you put a cheap $20.00 filter on the end. It defeats the purpose of buying good glass.
Personally I go with School of thought 2 and here is why: I want the clearest glass I can get. Oh, and due to the wonderful laws of diffraction most scratches cannot even be seen in the final photo. To protect my lenses I do two things. I am very careful with them and I always use a lens hood.
The world of professional photography is split about 50/50 on this issue. This tells me that no matter what you decide to do you can get high quality images. The choice is simply up to you.