I've moved 3 times since I got into DVD, and a couple of my cases have a couple of marks, a couple have slightly torn plastic, and a couple broke the spindle (those were quickly replaced). But the case is just as important as the disc, because without it, the discs would be ruined. Most of mine are in very good to immaculate condition, and those that are damaged I replace.
My snapper cases used to get worn around the spine where the cover bends. I have since put the discs into amarays and printed covers of the net.
I have had the glue come of on a corner of an amaray which made the clear plastic sleeve come off.
I also have the second release of the Dune miniseries, which comes in that book type packaging. I have had to leave the clear packaging on it, as it would get ruined having just a thin cardboard cover.
Seriously- this is why I at one point hated the Amarays and loved the snappers - in the very early days of DVD. The amaray covers get little scratchmarks on them from sliding every time you take them out from inbetween two other cases. However, this is not as bad as corner-dents on snappers.
Mine stay in relatively good shape, but recently I lent Band of Brothers to a friend of mine and he dropped it in a parking lot! This normally wouldn't have been a big deal, except that it is a heavy tin case, and now it has a huge dent in it. So now I lend out things like that in multi-disc keepcases. Speaking of which, does anyone know if there is a way to replace the Band of Brothers case? This dent is driving me nuts.
The unfortunate thing is the majority of my case damage is done when opening up the case the first time. Mostly wounds from those silly anti-theft stickers. I have many discs that have tiny punctures from fingernails digging down to pull up the corner. Also have covers that have shifted in the sleeve prior to the sticker being put on therefore when the sticker is removed, it pulls up part of the printed cover. Every time this happens I think, “I’ll have to be more careful next time and inspect to make sure the cover is sitting in the case square, but I always forget :b
I don't actually put my DVD cases on a shelf. I have these two big boxes, each with two drawers specifically designed to accomodate DVDs. Each case has its own slot, so the cases don't actually touch one another. It keeps them away from prying eyes, keeps the dust off them, and keeps the cases in pristine condition.
I would recommend them, only I live in the UK and can't even remember where I got them.
I buy most of my DVDs at a used store in my area. Unfortunately, a LOT of people seem to have this problem opening their DVDs, as about half of the discs I buy have these scars. I've replaced a few cases already. One day, I'll replace them all...
Anyway, it's really easy to avoid doing this. Just peel the anti-theft sticker from the top of the case, where the hard black plastic is exposed. This should easily rip the sticker in half, allowing you to peel it off of the clear plastic without damaging it. It's just as fast and even easier than trying to do it the way you described.