Drill instructors start out as Marines with a Military Occupational Specialty or MOS. Translated that means they are coming from a job that they do in the Marine Corps. They bring with them knowledge and experience from that job. Additionally, they bring with them the knowledge of what fleet life is like and what to expect after graduating from Marine Corps boot camp.
As a result of their MOS experience, drill instructors can offer valuable advice. This comes only at the end of boot camp when drill instructors transition from screaming machines into a mentor type role. It is at this point that new Marines can ask questions about what they can expect after graduating boot camp. Many drill instructors will have the same MOS as some of the recruits they are training. In these cases, much can be learned. New Marines can find out where their school is located and how long they will be in school.
By the time a Marine becomes a drill instructor he or she has typically been in the Marine Corps for about four years. They must reach the rank of sergeant (E-5) to be eligible for drill instructor duty. Marines volunteer for the honor of becoming drill instructors. They must meet the physical fitness requirements first. That means they must be in top physical shape in order to successfully complete drill instructor school. Drill instructor school is considered a “B” billet.
A drill instructor’s tour of duty is three years. They may wish to extend their time on the drill field after that and can be assigned to support positions in different areas such as a martial arts instructor or combat swim instructors. They can also be senior drill instructors, Series Gunnery Sergeants, or other positions. When they have fulfilled their duty, drill instructors can return to their MOS, taking with them all that they have learned.
The point is that drill instructors bring with them not only the knowledge of how to transform civilians into Marines but they know what life is like beyond boot camp. Drill instructors can be good for more than screaming and threatening death to impressionable recruits. Listening to them when they want to talk about their experiences is about the smartest thing a recruit can do. If you ever get a chance to talk to a drill instructor outside of the confines of a boot camp setting, take advantage of the opportunity. Although recruiting duty is also considered a “B” billet, some may have been drill instructors in their Marine Corps career. That, or they can refer you to Marines who have been drill instructors so that you can gain useful insight before you ship out.
Source: Personal experience