i own a set of B&W 801 series 2 with Kevlar cones which were never played very hard never in direct sun light which i purchased way back in 1984 all i have done
is to keep the cabinets oiled so they would not dry out and the dust off the covers with the original brush i received with the speakers, I am using a Krell built
Bass alignment Filter which was designed for that series along with bi-amping and they still sound as good as the day i purchased them.