My house is somewhat dusty - nothing much I can do about it except clean regularly (which sets my hay fever off).
My Ducky SHine came with a plastic dust cover which I try to leave on as often as possible - definitely overnight and when I am at work during the day.
It doesn't stop the odd dust particle or hair falling on the keyboard during normal use, but I am hoping that it will stop needless avalanches of dust burying the keyboard in the short term. That was a slight exaggeration, but anyway.
I have not had mine for long enough to notice any significant difference, but so far so good. Can't be bad.