<p>I agree with everything in the above post. It also depends upon the individual program, the instrument, etc.</p>
<p>In my S’s case, the marching band was a big deal at his school, and very time consuming. He did it only one year, because he realized it was taking away from his long-term musical goals. His directors were not happy with him, but his private teacher was. His private teacher felt that marching was going to hurt his embouchure.</p>
<p>There are not a lot of conducting classes for undergrads. It’s mostly a grad school pursuit, and the few I know of who have gone on to conducting were folks without marching band backgrounds, (either string players or foreigners) so I have no data points.</p>
<p>The drum majors at our school were chosen only in part for their musical ability, but more for their leadership (read: popularity - ability to get the other kids to follow them) and none pursued music later.</p>