Yes, I learned long ago to switch hands. I have a solid shaft, gearbox driven trimmer, so it throws debris into the bed if you move left to right.
I am naturally right handed, and that is the most comfortable. When needing to do detailed work, I do use trigger in right hand. However, for routine travel along edges of beds, I am always working with trigger in left hand, walking forward. Yes, I've "been there, done that" with the stupid events of walking backward. Also, walking forward, with trigger in left hand, allows me to move more quickly than walking backward. On a given trim job, I am often transferring one hand to the other. It is easy and quick (trimmer head slows only a little on the transfer before the other hand is back on the throttle).
Bottom line: learn to work with both hands.