How long do good speakers last?

It's all relative, right? Anywho...I have a set of Mirage M760s I bought in the late 80s. I still use them today. I recently acquired a set of Spendor S100s. Comparing on the same system the Spendors offer a different space of sound but I cannot yet say they are significantly better. Tomorrow I will be picking up a set of Focal Kanta 2s to also compare. I am hoping they will be better than both the Mirage and Spendors. I am using a McIntosh MA5200 integrated with a Rega RP8 with Ortofon Red2 cartridge, and McIntosh MCD-7008 CD player. With that said, "good speakers" should last a life time. Some maintenance costs may be necessary and very well is worth it.

Talk about "vintage"?  I am still enjoying my AR-2ax speakers from 1969!  The original ten inch woofers utilized rubber surrounds that have never needed replacement. 

I did have to replace one of the mid range drivers after about ten years - the corroded level controls in the 1980's,  and a burnt out dome tweeter just last year.  Fortunately, Parts Express carries a substitute AR dome tweeter for about $20 that matches the original perfectly.

These speakers still sound as sweet and natural as ever - especially with the latest improvements in analogue and digital sound sources!

As long as the spider and surround is good so are the woofers which take the most beating. I have witnessed all paper cone woofers last 35 years in a Leslie organ speakers. The HF longer. Mid and high frequency depends  on componenent material used and engineering design.

I had ac pair of JBL Laners go 20yrs before the woofer foam started to go bad

I've got a  pair of 1959 JBL Hartsfield the 15inch woofer is still in good shape after all these years.
In year 2000 I bought a pair of Klipschorn the 15 inch and horn driver are still in good shape.
In April this year I purchase my 3rd collection of JBL Everest DD66000 used by the last owner  who had them since 2009.
I prefer  drivers are made of cloth treated surround it will last for Donkey's years.
I had many other pairs of speaker with Form surround they last 3 to 5 years in Tropical Singapore.
So I only purchase the once with cloth treated surround. I am very happy of my purchase of my three pairs of speakers in my collection and I do know they will out last me. at age 67 years.