Any horse can benefit from a change-up. Take a barrel horse on a trail ride, jump your dressage horse, ride your trail horse around some cattle. New experiences engage a horse's mind and build confidence. If you focus too much on a single thing day after day, your horse may learn to resent it. Your horse can get sour from too much ground work. The horse is meant to be ridden and is a very purposeful animal. Your horse wants a job and purpose.