"Vintage" speakers...good idea?

To feed my stereo habit, I'm toying with the idea of buying a pair of "vintage" speakers, like the old classic JBL L series or something similar. Many of these speakers are up to 25 years old, but can be found with their foam surrounds repaired and in otherwise good condition. My question is, do other parts of the speaker wear out? That is, other than the obvious physical disintegration of the foam surrounds? What is the average life expectancy of a speaker?

Thanks!
John