Marching makes up like half the activity of marching band
Marching makes up about 25% of daily life for a solider. We had PT formations, morning formation, weekend safety briefing formations, formations for training sessions, etc etc. If you have an element of troops, of any size, and they need to move from Point A to Point B, you're marching there.
Anyone who has served longer than 3 years has done a pass and review.
Anyone who has been to a perm duty station has had a class A inspection.
Anyone who has ever served has marched daily, in formation, from point A to point B.
Double time is a marching speed, aka running, and you have to run in step.