I saw an article in The Audiophiliac asking “How long should your hi-fi last” It says: “So it makes sense to put the bulk of your hi-fi dollars into speakers, amps, and turntables. There’s almost no chance a technological innovation will come along to render obsolete any of those three items.”
I’ve got to agree! There have been technological changes to speakers but they concern magnet materials (neodymium vs ceramic vs alnico) and some cabinet and crossover designs. There have not been any changes that have caused your speakers to become obsolete. If anything, vintage speakers are often valued more than newer models unless you get into a select few high end products.
Speaker DO NEED REPAIRS. They experience wear and tear and need upkeep but that does not diminish their value in any way if the repairs are professionally done. So the answer to How Long Will your Speakers Last is generations. Invest in them now, enjoy your tunes, and add them to your will so the kids won’t have to fight over the “good stuff”