Like pretty much everyone else has said... I shave with both hands.

I'm still learning to shave with the non-dominate hand, but I improve with each shave.

There are places and angles that just make sense for the non-dominant hand to come into play... it's much easier to hit several spots on the left side with the left hand... similarly, the right side seems to call for the right hand...

I recall my first few shaves where I had my arms all tangled trying to scrape the left side of my neck with my right hand and skin strech with the left hand... a virtual game of twister.