That's kinda what I'm getting at. When I go to the beach, my eyeglasses end up with a film of salt mist that requires cleaning. Whenever I would ride my motorcycle along A1A, the first thing I did when I got home was to hose off the salt film.
So, everytime I go shooting at the beach I have to vigorously clean my camera lens filter. Without the filter, I would suspect the grinding effect of debris on the lens glass. Any dust (city smog, etc.) would do the same.
Yet, when I research, many refuse to use a filter. All I'm looking for is real world advice based on experience; not a yea or nay battle. No one is forced to contribute.
99% of the time I have a filter on my lenses. Not so much for impact damage, as is the common battle ground over whether to filter or not to filter but for some of the very reasons you point out and are often overlooked by the "You don't need a filter" crowd: there are other considerations *besides* impact damage. I shoot at the beach a lot and I shoot in the desert a lot.
Salt spray, bird poop (damn seagulls!) and what I call "beach schmutz" (if you shoot at the beach, you know what I'm talking about), is not something I want to be wiping off my front lens element... Ever. I just don't. It's not that I'm not all that concerned about damage, it's just a pain in the ass. So much easier to remove a filter, run it under warm water and dry it off.
Hoya HD filters are amazingly easy to clean this way, it's like they're Teflon coated or something. Then of course there's shooting in the desert...
Desert sand is not like beach sand *at all*. Desert sand is talcum-powder like in consistency, gets EVERYWHERE, sticks to EVERYTHING and is delightfully abrasive. This too is not something I relish removing from the front lens element. All "need" aside, I just don't want to do that. I find it much easier to remove a filter and run it under water to clean it. Even if I don't have running water it's a heckuva lot easier to clean a filter in the car or in the field than it is, say, a big 70-300mm lens. And if something *does* go horribly wrong it goes wrong on $100 filter, not a lens costing eight or ten times as much.
Lastly,
I shoot with CPL filter almost all of the time because I like the effect it has on my shots when shooting outdoors. There's a LOT of what I call "adverse reflective light" out there a CPL removes and I think it gives outdoor shots a sort of boost in saturation and clarity that you can't get any other way, including in post processing. It's kind of one of those things: you don't really notice it until you see it removed. All my lenses wear CPL's and only come off when they need to for specific situations. Once we're back to Situation Normal, the CPL goes back on.
.....