I do use UV( protection filters) when I am going to be in an environment where I will have the need to clean the front element frequently. Places with conditions such as blowing dust, water spray, ect.. i would rather be rubbing things off a filter than the lens front element.
The only lens I have ever lost to damage had a UV filter on it when I slipped and fell on a slippery rock in Iceland. Just as has been noted in this thread, the UV filter broke, and pieced dug into and scratched the front element of the lens. The lens also sustained some internal damage that was unrepairable, so total loss. Fortunately 100% covered by insurance.
Steve Perry did this set of experiments that seem to confirm my use of the filters.
