That's not true. My daily driver rides on 40 year old (started out near NOS) rubber with zero issues. Good traction, good ride and compared to the tires made today, incredible tread life.
If there are no signs of severe dry rotting, or broken coards, or flat spotting, there is NOTHING wrong with using old rubber. If I had a choice between Repro, or good NOS, I'd take the old stuff any time. You just can't get quality like that anymore.
