How long do good speakers last?


I just ordered a set of Sonus Faber Olympica Nova Vs, my first foray into nice speakers. I turn 51 this month and am hoping these will be the last speakers I ever buy. But it got me to thinking - how long should I expect these speakers to last? Or any good speakers for that matter? Does the foam eventually break down? Issues with general wear and tear? Appreciate your perspectives!
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My DQ10's still sound wonderful.  All original except a re-foam.  They could be 40 yo......
have a pair of realistic nova 6 speakers dating from 1971. they still work as designed. a pair of magnapans from 1982, they still work as designed. a pair of thiel cs.5 speakers from the late 90s that still work as designed. newest ones are a pair of vandersteen 1ci speakers that are only a few years old. 
I bought my Tannoy 638’s when I was in the Navy in 1994 on a port visit in Dubai. They are still perfect, though I have replaced a blown tweeter once. 
@oldhvymec....Wow.....

"Infinity InfiniTesimal RS 0.1. 1978 I have 2 pairs...."

I remember listening to a pair of them and thinking:
 "..these would be spectacular in 2 pairs....and a correctly sized sub..."

Did you?  Do you now?  Just curious...;)
If there is not much ultraviolet from the sun on the driver's I bet the electrolytes are bad within 10 years... Or go bad. 
Depends on temperatures and hours of playing. Crossover rebuilding can improve and extent the selflife. Another advantage is no a days there are much better electrolytes, improves the sound a lot.