Stylus/cantilever stiff and noisy--WARNING!

So you can estimate compliance by "feel"?  The specific issue you cited in your OP is a common phenomenon not necessarily related to aging of the suspension and more related to the inherent microphonics of any cartridge.  The cartridge takes physical motions and converts them into an electrical signal.  So do microphonic vacuum tubes.  And so do microphones.  Hence the term. And speakers take an electrical signal and use it to make air vibrate in tune to the music in the signal. Speakers are microphones in reverse. I wouldn’t "feel" the suspension of any cartridge for too long or too vigorously.  That could damage it if it was not already subpar.

Great post!  I've learned quite a bit from all the responses!  Thanks!

lewn wrote:

The specific issue you cited in your OP is a common phenomenon not necessarily related to aging of the suspension and more related to the inherent microphonics of any cartridge.  The cartridge takes physical motions and converts them into an electrical signal.  So do microphonic vacuum tubes.  And so do microphones. 

lewn, you ERRONEOUSLY used the term "microphonics" in your first reply, and maintain that error. I am also guilty of copying and pasting from that post. 

This is NOT really a microphonics issue. It is (roughly) a transduction issue, purely mechanical in nature and undesired consequences that occur.

Suspension rubber getting hard with age IS an issue, but, I have not experienced nor heard of this problem being manifested by increased needle chatter.  It is usually heard in the signal itself--mis-tracking, buzzing, etc.  

I suppose it doesn't hurt to try to revive the rubber by spraying something like WD40 if the cartridge is not a high priced item, but, I would never do this with any cartridge with a non user-replaceable stylus that is expensive.  There is no way to know how any chemical will react with any parts of the cartridge, particularly in the long term.

OP,

I never used that MG brand, but stuff like it works for me on my rubber rollers, I forget what brand it is.

lewm

I would only try it on something I thought was abnormally stiff or dried out, as a last resort before discard or rebuild. Some of us are less klutz and have many small tools, or we modify a tool as needed to accomplish something. 

While Ray checked half a dozen cartridges for me, including vintage AT150 and two AT160’s, all 3 with AT160ML Microline on beryllium cantilevers, Steve Leung at VAS mentioned how remarkable Audio Technica’s suspensions are, they seem to last forever. 

I put a sun shade inside my cartridge case on the windowsill behind my TT, but I think I’ll move it away from the suns rays altogether.

I have forced air hvac system, I blocked the air vent at that end of the room years ago, it’s left of the left speaker, I didn’t want to dry out the 15" woofer’s cloth surround/paper cone prematurely, and also want to avoid air borne dust.

Sometimes, when listening, I turn the system off to avoid any hint of fan noise or air movement, even though it is the far end of the duct.