I used too, until I saw pictures of comparisons with and without. Even with cheaper lenses (assuming lower quality). A direct hit to the main lens caused very little marks on the glass (using slide hammer, I think 3# slide). But a lens with a cheap filter on the front. Would get several marks (from the broken glass of the protector hitting and marking the good lens glass). The test lenses were all MF lenses from different brands. Would have several of each one (same exact lens). One would get the filter, and other would have nothing. Believe it or not, the lens barrel / actual lens piece mount would break more often than the glass (again the cheaper lenses). So, for the most part just chips in the glass were the worst, until they used more force than just letting the slide fall on the slide hammer. After I saw that article. I thought to myself. How thick is that filter. They are all pretty thin actually. They actually take less abuse than the lens itself. And when they break, cause more damage than if it had not been there in terms of marks on the lens.