Ya know how the sales person always tries to sell you a lens filter for your shiny new camera? It usually involves some pitch about how one day you’ll be glad you paid the $20 bucks to protect that front element from all sorts of freak occurrences yet unnamed. Buying all my newspaper’s video equipment online, I guess I kind of missed that lecture. So yes, I now regret not having a filter to protect my Sony Z1U lens.
At first, I thought the out of focus spots I was getting on my last few videos were from something on the lens. Under further examination with a magnifying glass, I found small pits in the front element. I’m not one to abuse my equipment. On the contrary, I’m obsessive when it comes to protecting it. How the hell did I get a dozen mini chunks taken out of my lens? After little detective work, I just had to groan when I figured it out. I’m pretty sure it happened during this video of an artist grinding on a metal sculpture of a gorilla. The shower of sparks captivated me. The low angle shot is when little bits of molten metal struck my lens. Damn. I packed it up and sent it to Sony service this week. I feel naked with out it…
Mastering Multimedia 
Colin – Sorry to hear about your unintended lens grinding.
I too learned this lesson the hard way, but fortunately on a replacable lense. My prized f1.2 50mm lens for my old 35mm film camera eventually got bumped. While the glass was okay, the filter ring threads were a mess. Since then, I put UV filters on all cameras including and especially my professional video cameras that do not have replaceable lenses. Sometimes, like shooting towards the sun, I still have to remove the UV since I can never seem to get the glass clean enough!
Fortunately a TV photographer colleague pointed out how vital those protective lenses can be and I have yet to buy a camera of any quality — still or video — for which I did not also get a UV lens.
There are plenty of useless (or at least worth much less than you pay for them) accessories people will try to sell you if you you do your research before you buy, you’ll know which ones you need and which ones simply pad someone’s commission.