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
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.
I am greatly enjoying a pair of Acoustic Research 2ax (circa 1969, made in Cambridge, MA) that I bought at a local used electronics/audio shop here in Eugene, OR. I refurbished the cloth woofer surrounds with new doping compound, and replaced the crossover capacitors and L-pads. I also had to replace one of the super tweeters and replaced both after finding an original used pair. So far so good.  They sound absolutely wonderful in my small, hopefully temporary, living space.  Not bad for about 47 years of solid audio service.