My older set of speakers are Sierra 1s which I purchased used in 2010; they were purchased by the original owner in 2009 so are coming up on 10 years old. I certainly have no complaints about them currently, they sound as good as the day I got them. I'm just wondering if there is any schedule of preventive maintenance that should be done to keep them functioning well for decades to come - something like replacing the rubber woofer surrounds or the crossover caps?