Technical assistance on musical instruments, for a concert or a recording, has been an increasing demand in recent years.
Indeed, the costs incurred for your important dates will be without return in the event of a technical problem on your saxophone on D-Day. A financial loss, not to mention the image that this can reflect if you are already on stage.
Technical assistance allows the musician (pro or not) to stay focused only on his job, on his show.
This practice, like guitar tech for guitarists or drum tech for drummers, has existed for many years in the United States. The musician and his technician go hand in hand.
My experiences in this area: Zenith, festivals, studio recordings and TV event (Canal +)