How long do speakers last?

You could contact DCM directly and get heir advice. Their phone is 877-326-5683, or thru their website:

www.dcmspeakers.com

I'm sure they still work on older speakers, You could perhaps just send them the drivers for rehab. I'll bet they can even sell you a new grill/sock.

It depends on the material and the enviroment.
Here is a pdf file on Rubber Products: Recommended Shelf Life
See Table I on page 5 for type of rubber, common or trade name and the shelf life.

Billy doesn't sound as good as he used to. Mayebe he was left in direct sunlight.

Rich, I thought the table you referred to was very interesting. Mainly, I was surprised to see such relatively short lifespans for materials that I thought lasted much longer (like silicone rubber and neoprene.)

Might be a good reason to get new cables and speakers every 10 years??

I drive a 33 year old MB that my dad bought new in '72. I now have visions of walking out one morning and discovering all the electrical insulation has turned to dust over night -- yikes!!

Luckily I don't have any rubber parts (so far!) but now I think I understand why some women are concerned over them ;~))