the platoon leader has extensive prior experience as an enlisted member or warrant officer before being commissioned as a lieutenant, it is likely that the platoon sergeant will have a greater wealth of military experience due to the disparity in military service length between a new lieutenant and a sergeant first class (typically a platoon leader has less than three years of service, whereas a platoon sergeant has from 7 to 15 years of service). However, service experience is not a prerequisite for commissioning and command. Rather, as has been since the beginning of professional armies, the privilege of and eligibility for command is usually predicated primarily on rank and is entrusted to those who have earned it, on the combined basis of: innate aptitude (leadership and management) and intelligence (intellectual and emotional); completed education (civil and military) and training (tactical and technical); and demonstrated skills (physical and conceptual) and competencies (practical and theoretical). Therefore, the platoon is usually commanded by a commissioned officer (normally a second lieutenant) as his/her first real command position after commissioning. Nonetheless, the wise and successful newly commissioned officer takes full advantage of the experience of the platoon sergeant by readily seeking and accepting the advice and counsel of a more experienced soldier and leader. Therefore, the platoon sergeant functions as the crucial conduit of interface between the soldier and the officer by bringing the experience of a senior noncommissioned officer into a sort of "on-the-job training" for the junior company-grade officer, helping to enable the officer to prepare for subsequent increases in levels of command. On occasion, when a sergeant first class is not available, either organically within the platoon or from another unit, a responsible Staff Sergeant (E-6) will probably be appointed to fill the platoon sergeant position instead. Here is an excerpt from the Army's Field Manual titled "The Army Noncommissioned Officer Guide" (FM 7-22.7). "While the 'Platoon Sergeant' is a duty position, not a rank, the platoon sergeant is the primary assistant and advisor to the platoon leader, with the responsibility of training and caring for soldiers. The platoon sergeant helps the commander to train the platoon leader and in that regard has an enormous effect on how that young officer perceives NCOs for the rest of his career. The platoon sergeant takes charge of the platoon in the absence of the platoon leader. As the lowest level senior NCO involved