Proac Response 2.5 - How long will they last?

indoors..maybe forever. don't let them outside without a leash, or a tall,fenced-in yard

If they are foam surrounds on the drivers then maybe.. Rubber should not really ever have a problem, unless they dry out, but I have seen people use a type of armorall product and refresh them like brand new with no downfall. Other than that leave em' alone, unless you want to put far superior capacitors into the crossover circuit, not only would this ensure the caps are not dying which they can slightly from my understanding over the years (go out of spec.) or whatever, but it is also a credible sound upgrade.. Something like cardas golden ratio caps, Sonicap, Mundorf.. etc.. Are pretty much guaranteed to be better than what is in there stock.

One thing great about the 2.5 is that the replacement drivers are well-known and available.

http://www.geocities.com/diyproac25/partslist.htm

http://www.speakercity.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=SC&Product_Code=D2010-8513-00&Category_Code=SSTW

http://www.speakercity.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=SC&Product_Code=18W-8535-00&Category_Code=SSMB

I owned a pair of 2.5s for three years that were from the late '90s and loved them.

One day, I plan to make the DIY versions with a veneer not commonly used on speakers.

My 15 year old (?) Proac RS2s still sound great. I think the usual "failure point" for speakers due to age is the surrounds around the cone. You might want to look at them to see if there is any cracking...

eventually the foam rubber surrounds do wear out, either just losing flexibility or actually tearing. you will be able to buy replacements when that happens; proac just uses scanspeak drivers - although they're branded 'proac' and might be a little different (I'm sure they'll claim they're really different).

one thing to consider is whether the speakers are exposed to full sun; that can speed up the deterioration of the foam surrounds. if one gets more sun than the other, switch the speakers every once in a while to even out the exposure.

otherwise, it's going to be a function of how much you play them and how loud. there's no reason you shouldn't be able to have these speakers for decades if you replace the drivers when needed. most of what you're paying for with speakers is the cabinets, not the drivers.

p.s. when you do replace the drivers, have it done by a qualified techlll