Also used for Winter Guard, Indoor Percussion, and Jazz ensembles. After marching season kids were never required to stay more than a few times a month. Guard/IP/Jazz were all voluntary and therefore their choice, (those were also never for a grade and never needed to be).
Assistants and head never stayed more than 3 days a week outside of marching season unless they wanted to.
I've never really understood the people that do 5 days a week after school sectional plus Saturday stuff, (especially at the MS level). If it takes that you need to better organize your classtime and play more appropriate music.