For out-of-unit leaders serving outside their home wards in Young Single Adult wards and stakes, the General Handbook specifies that the calling is normally for no longer than 3–5 years:MFBarnett wrote:It would also be helpful to have the standard or suggested time frame listed with each calling. (For example, bishop's are generally in for 5 years in our area. Is that the usual worldwide?)
https://www.churchofjesuschrist.org/stu ... e_number30
That's the only specific guideline for length of service that I'm aware of.
EDIT: Missionaries and mission presidents also have specific lengths of service.