If I could expand on the question a bit ... when do the speaker manufacturers design for the optimal sound to be heard? Immediately out of the box or after an extended break-in?
All speakers will "give" differently over the course of their lives. I've re-coned speakers before (AR-14's, so not a true high end set) and didn't notice much difference so this could be a moot point and the difference in mechanical resistance over time may be trivial.
I've heard that the capacitors in the cross-overs do need to be replaced after 10 years or so. I believe that the longest speaker warranty is about 10 years (e.g., Thiel), so I would be safe in assuming that 10 years is a reasonable expected speaker life. If it still makes you happy after that, more power to you. Replace cones, replace some of the electronics and away you go! The box may need to be tightened too, I guess. Wow, there's a lot to consider once you think about it.
All speakers will "give" differently over the course of their lives. I've re-coned speakers before (AR-14's, so not a true high end set) and didn't notice much difference so this could be a moot point and the difference in mechanical resistance over time may be trivial.
I've heard that the capacitors in the cross-overs do need to be replaced after 10 years or so. I believe that the longest speaker warranty is about 10 years (e.g., Thiel), so I would be safe in assuming that 10 years is a reasonable expected speaker life. If it still makes you happy after that, more power to you. Replace cones, replace some of the electronics and away you go! The box may need to be tightened too, I guess. Wow, there's a lot to consider once you think about it.