If you are in a marching activity, then it is IMPERATIVE that you have your feet in time. When you practice your show music, PUT YOUR FEET IN TIME by marking time, tracking, or even marching your drill on a field, your back yard, or parking lot. There are a lot of people who practice sitting down and only work on their hands. Then when it comes time to march everything falls apart.
Many drumlines are outstanding standing still, then dirty on the move.
So any time you play, MOVE YOUR FEET! You don't wan't to be an unbalanced performer. Practicing without moving your feet is like going to the gym and skipping Leg Day. And we don't skip leg day fam, because in the marching arts, every day is leg day.