There used to be school for elders in NY that lasted 2 weeks; imagine using all your vacation or having to take off work without pay and leaving your family and wife to do things on their own.
KINGDOM MINISTRY SCHOOL
This school was especially organized by the governing body of Jehovah’s witnesses of the Watch Tower Bible and Tract Society of Pennsylvania for the benefit of the overseers in the congregations of Jehovah’s witnesses. The training period is just two weeks in duration, but all day long. The congregation servants, assistant congregation servants and Bible study servants in the congregations of Jehovah’s witnesses are invited to attend this school. Generally these brothers come to the branch office location for the schooling; but if this is not convenient, they go to some Kingdom Hall in a city where they can receive this two-week course. The classes usually consist of twenty-five students, but all of these men are ordained ministers.