How long should high quality speakers last?

it’s a function of materials used and when they deteriorate. Foam surrounds have a 20 year(?) life. Anyone that recones drivers should be able to answer.

My experiemce….I heva 20 year old thiel 2.4’s that as afar as I can tell sound as good as the did 20 years ago. They were 4500 at the time, which I would call resonanbly high end. Generally their reviews are mostly positive.

Upgrade? I see no reason to, An upgrade would likely be expensive, thus costing me 16k or more. Seems silly and I’d probably be lucky to get away for 16K for the pair,

I had Bill at Great Plains Audio rebuild my Altec Lansing VOT 416-8 woofers two years ago. He reconed them with OEM parts and remagnetized the 2.4 lb alnico magnets. They were rated at 12,000 Gauss when new. If you drive the speakers hard the magnets will demagnetize.. These speakers were from the 50's and I still love their sound and prefer my Altecs to my Theil CS3.5's

When Alnico drivers have partially demagnetized you will notice a difference in efficiency and a noticeable loss in the higher frequencies. An alnico driver in need of recharging sounds kind of dull, and doesn't have as much transient jump. Basically, it sounds dull.

Speaker magnets can be regaussed by Bill at Great Plains Audio in Oklahoma City.

High quality speakers should literally last a lifetime or more provided: (1) the user does not damage them, and (2) they're kept in a suitable environment free from extreme temperatures and moisture (i.e., indoors).  I have a set of Klipschorns that are pushing 50 years of age and they are still performing as expected.

YMMV but I purchased a pair of ADS L810 series2 in 1978. Used them sparingly until about 6 or 7 years ago and passed them down to my little brother. He is still enjoying them today. They have survived many moves but still play like new. All original parts.

Of course, all of these are anecdotal and speaker design, quality and your luck will determine how it turns out.

@unreceivedogma wrote:

Did I say “sound the same as new”? 

I did not. 

However, I obviously would not still be using them if I was not getting anything less than outstanding performance from them. 

It appears the post you were replying to has been deleted, but nonetheless I'd say you would definitely be in your right to claim your vintage speakers sound "like new," also being they have been serviced regularly. Who really, from actual experience, refers to and knows about the sonic difference between more or less brand new, properly run in Altec's and their decades old, well-kept equivalent? Demagnetization of Alnico magnets in particular, as has been touched upon, is really only an issue with excessive heating of the magnet from large voice coils or shock treatment, and any natural degradation of magnets is hardly anything other than academic in nature.

The real takeaway here is that such drivers, even decades old, are so transiently alive, dynamic and natural sounding that many newer, lower efficiency modern drivers seem stale and lifeless by comparison. Speaking of sonic detrimements due to aging here misses not only its relevance but also fails to take into consideration an unbiased assessment of these older designs and their merits.