Planting with the same hand will make you lopsided. Working your body one-sidedly will cause distortions of strength and flexibility. That imbalance will make you more prone to strain and pain. This may very well be a major reason why such a highly fit industry as silviculture looses so much productivity and spends so much money recovering from musculoskeletal injuries (MSI). It amounts to close to a million dollars annually on MSI compensation if we include attendant injuries that muscle imbalance can contribute to. The remedy is learning to plant ambidextrously and this should be taught to every new planter and to any teachable vet.