I have been collecting for way to long and have found out that keeping cards in boxes or tins (without any sleeves) isnt very smart. air and moisture seem to find there way in and start to mold up and soften the cards ,as if starting to decompose. so I started putting them in a whole bunch of ziplock bags, pushing out the air , then sealing them . then I put them into boxes or tins. thats only for my commons/ uncommons though. rare holos I keep in binders , and my ex's and lv.x's in sleeves/ toploaders.