I had to audition for the Fifth Army band to be assigned there. Upon completion of basic training, I was sent to the U.S.Navy School of Music at little Creek Virgirnia which is the equivilent of a three year colledge level music school condensed into six months. I came in with the highest incoming audition score for a tuba player with a 3.29 out of a possible 4.0.
An assignment to a military band is a permanent assignment. However, Army protocol at that time, mid 60's, was to rotate personnel every three years to prevent stagnation in any location. Transfers were always to other band units.
If a person was assigned to one of the 'special' bands, ie The Army Band, West point Band, the assignment was considered more permanent and transfers were less frequent.
Each 'Army' 1st, 2nd, 3rd, 4th, 5th, etc had what was considered to be the 'headquarters' band where the band master also had oversight for any other bands in that 'army'. The Fifth Army band was a headquarters band. The headquarters band usually was able to get the 'pick of the crop' from each band within it's area and had a higher authorized strength than the smaller bands within it's area.
Being assigned to a band is easy duty, but still no guarantee of not being in combat. I am aware of at least 8 bands being in Viet Nam during that war and of several band members being killed there. Often when a band is transferred into a combat zone, they assume routine patrol and other duties like any other infantry unit.
Tuba ping! I was principal tuba in the VMI Regimental Band my entire cadetship! Of course, as an officer, I couldn't play in an Army band on active duty....