Beo;
The dust accumulation will happen over the years on any of the B&O music systems. One in the Alps, and one in the Tropics.
I have two BS 1 units, one from the product incept in 2001 and another purchased in 2003. Both continue to operate very well, although one was zapped plugging it in to the wrong mains supply ( the voltage converter and fuse were the only items damaged and repaired ).
Both units are placed on highly polished granite, so any dust is quite obvious and going to be noticed. The design of the unit attracts people to it like a magnet, so we keep the area clean at all times.
I wipe using a damp cloth each week, and every 6 months use a small hand-held battery powered vacum for computer and IC board cleaning for the CD changer and speaker inside the alu cover. When we are away or on Holiday, I unplug the units and cover them with the original plastic " pillowcase " from the B&O packing, and / or put them away in a cabinet.
Regarding degredation of sound, I have yet to notice any, but they aren't " cranked up " much, at least when I'm present. Tile flooring and masonry walls make a lot of skip and echo effect. Usage is primarily local FM, CD, ( A.AUX sourced ) N.MUSIC, N.RADIO, and as an inexpensive HOME THEATRE with a SKY SAT TV box. If the BS 1 is set on a small TV swivel, it can be used with a SAT box, PC, or MAC connection, and moved about to fit the audience.