Upload & Sell: On
Most photographers use a Uv filter on the front of their lenses to protect the front element. It doesn't impact on the image quality (some dispute this) if you turn around and bash the front of the lens into something hard you bust a $30 filter, instead of a $xxxx lens! You can also clean them with your shirt when out shooting!
Most serious photographers do not use a "protective" filter on the front element. Lots of new camera buyers are convinced that they need such filters by the sales people, or by other recently new photographers who bought such filters and now think others should, too.
The protective filters have no beneficial qualities at all in terms of image quality. In many cases they may not produce a negative effect either, but in other cases they can. Most commonly they can generate reflections between the rear of the filter and the front elements of the lens, and this is not uncommon in night photography when bright light sources appear in the frame. Less-expensive and lesser-quality UV filters can create other sorts of image quality problems including flare, loss in contrast, or even outright optical distortions.
The "insurance" value of UV filters is also rather dubious. It is undoubtedly true that there are a few unusual cases in which a frontal impact to the filter that might have caused damage to the lens is prevented or lessened by the filter. There are also reports of cases in which shards from broken filters, sometimes from side impacts that would not have struck the front element, scratch the front element. The cost/ benefit story for high quality filters also doesn't quite make monetary sense. While a filter certainly costs less than an expensive lens, a) it only protects from a small subset of possible modes of lens damage, b) the cost of replacing a front element is often little more than the cost of an excellent "protective" filter, c) the cost of adding expensive, high quality filters to each of your lenses often approaches the value of a lens, and d) very few photographers have a lens front element damaged in a way that the filter would have prevented it.
In a few rare cases when one is shooting with a sealed body (such as a 1-series Canon body) and working in a very hostile environment, the addition of such a filter might have some value. Thinking that you are protected by putting a filter on your lens while shooting with an unsealed camera body seems a bit strange...