Staff are assigned to duty stations on the basis of events in the countries in conflict and the needs of humanitarian operations. In principle, they are not free to choose where they will carry out their missions. The ICRC can decide to change the duty station at any time, if the circumstances so require.

In deciding where to post its expatriate staff, the ICRC must reconcile the characteristics of the post with the staff member's profile and with career planning requirements. It must meet operational needs while making sure each staff member's career follows a coherent path. In spite of the constraints, the ICRC encourages staff members to inform it of their aspirations. It tries to fulfil those aspirations if they are in keeping with a logical course of professional development. A data bank of all field and headquarters positions enables staff to express interest whenever a vacancy comes up. Staff can also tell the ICRC what they would like to do next, at the latest three months before the end of their mission.