Here's a question for you: Is there a difference between using a clear optical glass filter vs. a UV filter to protect your lens? In other words, if you don't need to be filtering UV because you're not shooting in the mountains somewhere, will a UV filter cause image degradation or color shifting at lower altitudes? I'll bet someone out there has done comparison testing or is this a question for Tiffen and/or B+W?
The other thing that's problematic is when some people shoot with UV filters, they store their lenses with those filters in place. That creates a medium for growth of fungus, mold and mildew on the front element (both inside and out) because lack of air circulation promotes those kinds of growths. Those of course, can lead to scarring of the front element which brings us back to the age-old question that I believe came up before photography was actually invented: "How much mold, mildew, dirt, dust and debris is enough to adversely affect image quality?
Take it slow ;>)
in 45 years I've never had that problem shooting from tropical rain fores to te sahara