How long do high quality speakers "last"


I am the original owner of a pair of ProAc Response 2 speakers. They are almost 7 years old, but have never been driven excessively hard. How long (i.e. useful lifespan in years) can I expect these speakers to "last" (i.e. no significant sonic degradation) if I care for them carefully? When they do start to degrade, what mechanical failures and sonic degradations can I expect to occur? Thanks in advance!!!
mshan
I have had one reconed. Have had some 20 years.  "Quality speakers last for decades if used within their comfort zone." I sold one pair which failed but a guy who was there told me that they were on the floor and they were bouncing up and down before they went.

7 years is just barely broken in!  Seriously, unless your drivers have foam surrounds, speakers should last a long, long time.  My Spendors have 15 years and should continue for many more.  The vintage drivers in my high-efficiency speakers date from the 1960s and 1970s, and they still sound great.  The woofers from the '60's were reconed a few years ago with NOS paper cones, but other than that everything is stock.