I know this is a hot and controversial topic, but I have never owned a vintage phono cartridge that actually had insoluble problems due to aging of the suspension. In my experience, a few spins on the break-in bands of the Cardas test LP have always worked to bring a long dormant cartridge back to life. What we can never know is whether it then sounds the same as it did at birth. For sure, there may be changes due purely to aging, but the nature of such changes is lost to the listener. The cartridge can only sound good, great, mediocre, bad, etc, with the attendant faults and virtues. I take them at their "here and now" value. I guess you could conclude that bad sounding vintage cartridges may have got that way due to age, but it’s only an educated guess. I can only think of one or two out of dozens that fall into that category, and those one or two were "pre-owned", which means they could have been abused by a previous owner.