UV clear protection window film

[djson1]

I know this has been discussed on here several times, but can anybody share their experiences with using UV protection film on glass cases?
Does it really help to prevent the signatures on balls (or any other medium such as photos) from fading?

I have this large glass case (it's made for DVDs) and I put a lot of my signed balls in there. The balls are housed in "UV protected" cubes, of course, but I was wondering if I should buy some of that UV film and apply it to the glass to further help prevent fading. But does that stuff really work?

I know it may be hard to gauge the actual effectiveness unless you are testing and comparing it to something similar, but just wondering if anybody has put their autographs behind UV protected glass and still noticed a lot of fading.

Any experiences shared would be appreciated...thanks.