What is "tours of duty"

Usage examples of "tours of duty".

Later, as a junior officer, you learn what the checkpoints are--what tours of duty are considered desirable for promotion competitiveness, what assignments spell out a dead end to your career.

He knew that smell, could remember it from his own tours of duty before he'd promoted up and out.

While Rodgers did his tours of duty on the ground, August flew reconnaissance missions over the north.

The party would really commence around five, when the men on the day shift arrived at Eagles Hall, and it continued until well past midnight, enabling the evening men to join in after their tours of duty.

The human and Heechee complement were sent back when their tours of duty were over, usually roughly the equivalent of three standard Earth years.

I hear that Deathworld 69 is really in this year for suicidal tours of duty.