Nearly all marching band music (not classic marches, mind) that I've seen in my five years of performing experience has been written without any kind of repeat signs. However, I've recently seen some marching arrangements of jazz standards that did in fact use repeat bars.
Printing in a "through-composed" manner seems to make more sense to me, as it would be easier for performers to annotate the sheet music as needed, and easier to coordinate drill charts with measure numbers.
Are these markings actually more common than I think?