Dually Mud Flaps Required?

I've been driving dually pick-ups in VA, WV and about 20 other states for the last 14 years. I've never had mud flaps. I never even considered it. My truck's have always passed the yearly vehicle inspection so it must not be required here. I rarely ever see a dually with them.
I go off road frequently and likely the mud flaps would get ripped off every couple of weeks anyway.