I would not even think about this issue for about twenty years. I would examine the woofers edges for deterioration of the tape between mount and cones. Nothing wrong with examining it early. I bought four 800 Series B&W speakers and ended up getting them all re-taped at around 25 years. Other than that, they should be good until you want better performing speakers. Typically for me that is every 10 - 15 years.
How long should high quality speakers last?
My Zu Omen Def MKii (rev B) are going on 13-14 years old. The speakers sound wonderful. I have no intention of parting with them. The speakers came with the latest ZU tweeter design. How long should I expect the speakers to last without any issues? I do not abuse the speakers and run them with my Luxman 595ase amp.