Speaker Lifespan

Barring a blown driver, tweeter, etc. How long before sound starts to obviously degrade? I have Mirage Bi Polars that are 12 years old. Not looking forward to replacing them.
I have a pair of JBL's from 1972 and no problems what so ever. Maybe the crossover caps start changing value over decades??
My speakers have followed me throughout my life, with various members of the family. My son uses my Monitor Audio MA8's circa 1990. My mother uses the first speakers I ever bought, Leak Mini sandwich's circa 1965. Mind you, she is pretty deaf now and I am not sure if she notices if sound is coming out at all, never mind deteriorating drivers.
So, a challenge, has anyone got speakers 41 years old still working. Leak, British engineering for you.
you need new speakers,then a new amp,then a new...... come on man,keep the econo goin'!!!!
It depends on the material being used, especially for the driver cone surround. Foam is (albeit musical sounding) very susceptible to rot, while rubber is more durable. I think the Xover components are not subject to degradation, because of the relatively low voltage of the signals and the low ambient temperature.

How about Goodmans Axiom 80s
Despite their really low power handling most are still going strong after nearly 40 years-and in many ways they are still the best sounding speaker ever.