Most of my VHS tapes have aged pretty well (20+ years) but there was one occasion when I ordered a tape from eBay of a 1975 TV movie called "Eric" (one of Mark Hamill's early films).

The image on the tape was almost totally gone- it looked like everything was in a blinding snowstorm. The color was totally washed out and the images were so 'faded' that only the very darkest areas were visible. I have no idea what could have caused this- the sound on the tape was fine, so I doubt that it had anything to do with being too close to a magnetic source.

I returned the tape to the seller and was eventually able to find another copy, which was in good shape.