longevity of good speakers

i am somewhat new at the audiophile game and i am looking for some advice on speakers. NOT SUGGESTIONS. my question is in buying a high caliber speaker like the verity ovations on the used market, with average play, approx. 20 hrs./week, how long can they be expected to play at their top form? in other words, if i buy a six year old set of good speakers, how long could i realistically expect them to give me great satisfaction?
Speaker electrical characteristics change as the drivers are heated.
Maybe a heated speaker....say running 50% of 'redline' for an hour or so may be even easier to damage.
Caps in crossovers also deteriorate with age. Letting them just sit in a closet is probably worse than running them daily, if not electrically abused in the process.
That reminds me,shipping speakers by air can cause the ferrofluid to leak,from the pressure change.
A properly designed speaker should last a lifetime with a little maintenance.
Vintage speakers were made a lot better and will last a lifetime....I love my sansui sp-5500 horn speakers with cryoed inside wires and all crossover parts cryoed!..Now all I need to do is put some of Alan Maher's CBF crystals on the crossover parts. Someone over on the audio asylum forum said these crystals works great inside the shells of a ac plugs and ac IEC connectors. He said it improved audio and video A LOT!...They now sell the crystals in bulk by the pound!
I have a pair 25 year old Wharfedale Diamonds. I had to do a little glue repair on the dust caps. The tweeters look like ones you could replace for $6 bucks- for the pair! No one can believe how good they sound.
Foam deteriorates, some people replace caps, but old cared for speakers should last a long long time.