One of my prized lenses is the Nikon 17-35 F2.8. I usually keep a HAZE or UV filter on all my lenses to protect the objective from impact or scratching.

Well, imagine my surprise last week when I went to remove the filter to put another one on and it would not come loose. Perhaps a little moisture got in and rust had got on the threads. I took it to the repair shop and got it back in a day. Everything is ok with it now.

Now I am storing my filters separately, until needed.

No report as to what they found.

There is no need to store them separately. Simply get into a routine of taking a swap or even a q-tip dipped in isopropyl alcohol or acetone and run it across the threads of the filter a few times until clean. Do the same to the the "receiving" threads of the lens. Let dry, replace the filter -- and you're good for another 3-4 months or so. (Just be careful to keep the solvent off the glass surfaces.)

If you happen to be using your gear in an environment that is extremely humid, sandy or dusty, then you'll need to do this more often, but 3-4 months is fine for the majority of situations.