How often should a UV filter be replaced

I was reading another post about lens cleaning and that usually like me they keep UV filters over the lens. Part of the reason is so I don't have to clean my front elements of my lenses, the other is added protection in case of stupidity or accidents.

But the thought came to me... How often should I plan on replacing my UV filters?

To date I haven't replaced any, but one is starting to look like it may start becoming unacceptable. I haven't noticed any loss of quality, but have noted a couple of minor scratches near the edges, it is also the one that has taken a touch of damage on the outer ring, making it a bit harder to screw on another filter (polarizer or IR). I suspect when the tripod head decided to let it down not so gently and it banged against one of the legs to be the culprit. Did I mention I am rough on my equipment?

Just a thought. Anybody else have any thoughts on this topic?

I think you've answered your own question. If the filter's starting to look shabby, it's probably ready for retirement.

I'll use a filter until either the screw threads get damaged or until the outer ring looks damaged. I've never scratched the glass.

---Bob Gross---

Probably from too many times going through bushes, rivers or maybe sand in the camera bag. That's what I get for taking pictures on location and why I have the UV filters on. Shore lines are the most dangerous places, darn waves try to get me. Did get my model once - no damage.

And the questions wasn't should that one be replaced, it was more of a budgeting question. How long should I expect them to last?
recognize the complexity of the question, just a thought that came to my mind.

The filter on your primary lens, on the camera and out in the open all the time while you dune-buggy over beaches and crawl through undergrowth - you'd be doing well to get a year or two out of it. The filter on your TS-24 which gets pulled out of storage once or twice a year in the studio - forever. Really, there's no expected life with a filter - there aren't any moving parts to go out of whack; it's just a question of how much abuse it gets while it protects your lens. If you're worried about its condition, it's time.

Just thought I'd mention that you really shouldn't screw a polarizer onto the UV filter, if you can avoid it.

Okay, even if we allow that a single layer of glass (the UV filter) has no significant image degradation effect, stacking a UV filter and a polarizer leaves us with 3 layers of glass (since a polarizer contains two glass layers). And at some point, you do begin to degrade the image by sticking multiple layers of glass in front of the lens.

As for your primary question - when to replace? - the other answers pretty much cover it. Replace your UV filter when it starts showing signs of wear (either to the glass or the ring) that impair its fit or function to an objectionable degree. With a lightly and gently used filter, this can mean replacing it every other century. With a filter that sees a lot of hard use under extreme conditions, it can mean replacing it at the end of every day's shoot.

If the damage to the filter is imparing it's function (wrecked thread) or its scratched enough to show on the image replace it. Otherwise don't bother. Scratches that don't show up on the final image don't exist (for all practical purpose).

When they get all scratched up like a good Bee gees album should be...

There's a good Bee Gee's album?

.... only when there scratched up....
[rimshot}

//thanks for being my straight man....