I've used two 6 inch hyperfans for about 3 years. One just died a couple of days ago.
I don't clean them and they were heaps dusty and it was making scraping noises for a couple of days.
It's probably my fault and I imagine it would still be going strong if it was pumping cleaner air from a carbon filter.
I love the hyper fans. I'm a big fan. I've always been impressed with how whisper silent they are on low speeds.
Well since that one died, I ordered another and it arrived today.
But I spend an extra $150 and got the model pre-built into a silencer! Ooooh baby is it good.
Now I'm impressed with how whisper silent it is on high speeds! Holy crap.
I'll aim to feed this silent beast cleaner air, a.s.a.p.