How long do speakers last?

My Acoustat Spectra 33's were built in 1988. 35 years old. I had the interfaces rebuilt last year, but the panels seem indestructible. I had the interfaces rebuilt as an upgrade, not because they weren't working . 

Enjoy the Music 

I have an RCA Photophone Shearer horn that has original drivers from 1938 it still sings and amazes even jaded audio designers. I have a lot of drivers and speakers from the 1940s to the early 1970s that are all matching specs. It depends on the build modern loudspeakers with their polymers and ferrofluids do not last that long figure 15-20 years most would need service before that time frame. Sure they may play but the fluids dried up in VC and the modern plastics break down capacitor values may also have shifted with age thus not meeting specs  

I bought my Kappa 7's off the sales floor (last pair in store) in 1990. 3 wives, 2 kids, 5 houses, 2 dogs, dozen cats, 4 integrated amps, 2 TT, 1/2 dozen tape decks, more cd players than I can count, 3 re foams later, and they are still my daily drivers. 

I'm so sorry @ieales, I guess you are a FAR BETTER expert on the freaking sound of the speakers in my house that I've listened to for 35 years and you've heard, um.....never.  Thanks for educating my ears.  As hard as it is to believe, some speakers that aren't used everyday or every month, are constantly cleaned and dusted even if not used, are kept in a 100% smoke-free environment and always kept in a climate controlled area, can have the internal components last WAY LONGER than expected.  Or, maybe I'm just lucky.

@secretguy -- I'm absolutely not letting them sit!  In the last two months I set up a 4th listening room in the house with the Polk Audio 10's.  I wanted to put together a simple system to play music with new gear I've bought over the last 4 years and never unboxed, so I hooked up a BlueNode Streamer and a Fluance RT-85 turntable with a Sutherland KC Vibe phono preamp to a Reisong A-10 tube integrated amp.  Perfect synergy with the old school Polk's.

One of the gradual degradation regimes most people don't think about is  demagnetization of the driver magnets. I have thirty year old Altec Lansing Voice of the Theater Speakers that I sent the woofers to Great Plains Audio for rebuild. They reconed, remagnetized the drivers, replaced the voice coil spiders and speaker suspensions. They are as new. 

The demagnetization occurs if you drive your speakers hard for long periods of time. The heat and vibration will disorient the magnet domains. This doesn't happen overnight, it's a gradual and accumulated process that can take years.