My R105/3 bought new in 89 I had the foam woofer surrounds replaced with a rubber type in 1990 and when I sold them in 2017 they still rocked. I biamped them with 200/325 8-4 amps at +104 average all the time and they just kept dishing it out. I regularly buy 10-15 year old speakers to enjoy the sound I couldn't justify new and haven't been disappointed yet.
Speaker Lifespan
Barring a blown driver, tweeter, etc. How long before sound starts to obviously degrade? I have Mirage Bi Polars that are 12 years old. Not looking forward to replacing them.