Not sure how it works for it works for the Stones but usually hired hands get paid either per gig or per week, since often promo appearances etc are made in addition to the usual live concert appearances. For a little insight on how this works, Andy Gibb wrote a great book called "Neighborhood Threat" about his tour with Iggy Pop in 1988. In addition to salaries, musicians and crew are often paid a daily or weekly "per diem"
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en.wikipedia.org]
"Per diem, or "per day," is a Latin phrase meaning specific amount of money an organization allows an individual to spend per day. Typically, though not exclusively, this is to cover travel and subsistence expenses.
Many U.S. companies and organizations use the per diem rate guide published by the General Services Administration, which provides rates for a number of cities in the United States."