There are few universal rules common to all Grand Lodge jurisdictions of Freemasonry (see Masonic Landmarks for accepted universal principles of regular Freemasonry). However, the structure of the "progressive" offices is very nearly universal. While the precise hierarchy or order of various officers within the "line" of officers may vary, the usual progression is for a lodge officer to spend either one or two years in each position, advancing through "the chairs", until he is elected as Worshipful Master. In addition, there are some offices that are traditionally not considered to be part of the "line", and which may be held by the same brother for many years, or may be reserved for Past Masters.