It might actually be fortunate that the tapes used for Apollo telemetry were manufactured in the 1960s, before manufacturers like Ampex and 3M started using polyurethane binders.

The polyurethane binders used from about 1976 to 1986 were prone to a problem in which the binder absorbed moisture from the air and turned into a glue-like substance. I've seen reels of 2-inch Ampex 456 which were so sticky that when you mounted them on a machine and hit "play" nothing would happen because the capstan couldn't exert enough force to break the tape loose from the heads. Tapes suffering from "sticky shed" could only be rendered playable by baking them in a convection oven to dessicate them- a process which took around 8 hours and carried some risk of ruining the tape altogether.

Luckily, tape manufactured before the mid-'70s didn't use polyurethane as a binder and isn't subject to this problem.

Old tape stock can be surprisingly durable. I've done trouble-free transfers of recordings made on Scotch 111- an acetate-based tape that was basically Scotch tape coated with ground-up rust- nearly 50 years after they were recorded.

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