depends on the manufacturer, I work on Pilatus and our mini takes 2 shifts, a phase 5 about 3 days. 6 minis and 6 phases are spread over 1200hrs of flight or 1 year. The military can adjust things if they need to since they are not limited to following the FAA rules
Compared to say, an F-4 Phantom. That dog took over an hour of maintenance per flight hour.
And they are much cheaper, as well. And meet the needs of the task at hand.
/johnny