Heat aggravates binder hydrolysis. It also causes tape to expand and contract producing creases, stretching and structural damage. Dirt and debris contaminate the surface of the tape and block playback machinery from reading the signal. Dirt also gets inside tape wraps, causing deformation and abrasion of the tape surface. Storage environments must be cool, dry, clean and relatively stable to maintain tape in good condition.
Proper storage can extend tape life by years or even decades.
If you are having problems playing back some of your tapes, you should consider taking action now before additional tapes deteriorate. If normal activity causes you to sweat, cough or sneeze, the environment is damaging your tapes. Open the container in which a tape is stored and sniff the tape. Check the interior of the container and any visible tape. Everything should look clean and uniform.