too many variables. in theory they should last forever. typically people managed to physically destroy them ( kids fingers spilt drinks, moving house etc.) before you wear them out. age probably hurts them more then use itself. stiffening adhesives & cracking will happen much faster if they are rarely used as opposed to frequent use keeping them limber for longer. cold climates and varying temperatures will hasten the degradation of the adhesives.
Hot Tip - ensure your speakers are never exposed to sunlight. a friend had one that copped morning sun for about 2 hours through a window and it needed new trifts in 4 years the other one looks brand new.
Hot Tip - ensure your speakers are never exposed to sunlight. a friend had one that copped morning sun for about 2 hours through a window and it needed new trifts in 4 years the other one looks brand new.