The Symbolic Masonic Lodge is governed by a Master and two Wardens with the Master having the control and authority over the Lodge, along with a group of other officers of appropriate responsibilities. The final authority in a Lodge is the "Craft" or membership. Most lodges meet once or twice a month, but some, particularly those organized for special purposes (e.g., research and memorial lodges) may meet monthly, quarterly or less often. A meeting specified by the by-laws of the lodge is called a "stated communication"; a meeting held at some other time which is ordered and authorized by the Master, is termed a "called communication". Most lodges (and other Masonic bodies) use an advancing line of officers; a Brother will serve one year in a position and then move up to a more responsible position the following year (if he has served conscientiously) in a regular pattern. This provides officers with experience at all levels of responsibility and allows for orderly planning of activities as well as their obtaining the information and knowledge necessary to properly govern a Lodge in the future. In some jurisdictions it is also necessary that a Brother serve a year as either Junior or Senior Warden to be qualified for election as Master of a Lodge; the principle of line advancement in office provides this opportunity.