My machine must be a record breaker.
I bought a top of the line JVC Hi-Fi 2 speed machine in 1984, which cost a mint at the time. It has proved to be the most reliable piece of hi-fi equipment I have ever owned, and it is still in working order. The picture quality on some recordings these days is not that crash hot and the hi-fi sound tracks often drop out forcing me to listen to the standard tracks, but it may be more the result of my ageing collection of tapes. A newer Panasonic (about 8 years old) is in much worse condition despite being used less.
However, if you have tapes which you want to keep for posterity, dub them onto DVDs pronto. My wedding films, originally transferred from Super 8, are showing quite a bit of degradation, and I will be tranferring them onto DVD by way of a DVD & Hard Disk recorder which I bought last Saturday. It is my understanding that recordings on tape deteriorate over time, even if they are in storage and not played.