Dust

I too live in AZ and dust is to us as mud is to others. 
I have a sheet that covers the TV and all components
Individual socks for each speaker.

Do they help? Yes. 
Final solution? No. 

But you dust 1/2 as often.

Assuming you use them.

oldhvymec,
Thanks for the silk idea. I'm going to try it!

I cover my Cary 211 FE amps primarily for protection from my cats but my VPI rim drive TNT turntable I cover to keep the dust off. All covers were made by Stereo Squares.

Lived in Arizona for 25 years... never covered. Have not in the ensuing 20 years. Never had any problems because of it.