I have probably close to 1000 cassettes, the majority acquired in trades over a few decades. My oldest cassettes date to the 1970s. I have yet to find a tape in my collection that does not play, or "went bad" while in storage. Maybe I got lucky? I store them all in case logic boxes in a closet. The bigger problem for me is, finding someone local that can service my decks for a fair price. I will say that the advice a few posts back to "unpack" the tapes before playing them (i.e. fast forward and rewind) is indeed sound advice.