Should you always mount from the left and what do Anderson and Parelli say about this tradition?

Both Clinton Anderson and Pat Parelli address the tradition of mounting exclusively from the left and both teach that it is an outdated convention with no practical justification in modern horsemanship. The historical origin — mounted cavalry soldiers carrying swords on the left hip needing to mount from the left to avoid the scabbard — is well documented and was a genuine practical reason for the tradition. That reason has not applied to civilian horsemanship for well over a century, but the convention persists because it has been passed down without questioning why. Anderson's objection is practical: a horse trained to be mounted exclusively from the left is asymmetrically prepared and will show resistance when mounted from the right — not because it is being difficult but because that context is genuinely unfamiliar. He teaches mounting from both sides as standard practice and notes that horses started with both-side mounting from the beginning show no preference or resistance on either side. Parelli frames it within his broader emphasis on developing a symmetrical horse. Many horses are already one-sided because of asymmetrical training, handling, and riding — always leading from the left, always mounting from the left, always turning the same way through gates. He advocates conscious symmetry in all ground handling as a way of developing a more even, supple, and balanced horse, and mounting from both sides is part of that commitment to symmetry. Both trainers acknowledge that real-world situations — a horse that spooks on a narrow trail, a situation where the right side is the only safe option — make right-side mounting a practical necessity at some point. Training the horse to accept it before the situation demands it is simply good preparation.