Depends on what tape and storage. My dad has a Teac M-10 that he bought brand new in 1970. This is a reel to reel tape deck and was well advanced at the time. He recorded a number of reels with music as he could play 4 hours straight. He also made a point of only using BASF tapes which were the dearest and best quality. He put on some tapes last Christmas and they played as good as the day they were recorded 40 years earlier. He stores the tapes in a cool, dark and dry cabinet.