In return for these benefits, the military asks for a unique commitment - something more serious than perhaps any other job. You are asked to protect your country, put your life on the line and be responsible for the lives of others. You will have to stay at the peak of physical fitness and many tough tasks (not just physical ones but mental and emotional challenges as well) will be asked of you. The service requires intensive and sometimes painful training and does not allow for carelessness or laziness because of the level of responsibility that rests on every individual’s shoulders.    

The U.S. Military is different from any other career choice you make because:

• Once you join, you cannot easily change your mind and quit; you are legally tied to this career for several years.
• Job security - once you join, you are tied into this career and it is almost impossible to get fired.
• You are choosing a career which may require you to harm other people and risk your own life.
• There is no 9-5, you will have responsibilities 24 hours a day, 7 days a week- it is a lifestyle more than a job.

When you enter the military, you are entering one of the most (if not THE most) culturally diverse job forces in the country. You will be able to not only work with, but also live with people from all over the country and all over the world. 

Each branch of the military is unique and offers different opportunities. Many people already have some idea of what branch they want to join - often because of family tradition. Each service offers a wide of array of job opportunities - there are some jobs in the Navy that you can’t get in the Army, some in the Army that you can’t get in the Marines and so on. 

Here are some of other basic differences:

Army
The army is best known for their tactical skills on the ground. Their air support comes mainly from helicopters (black hawks, etc.) rather than from planes or jets. Of all the branches of service, the army currently offers the most money in scholarships and reimbursement for soldiers who would like to attend college. The army is organized in Squads, Platoons, Companies, Battalions, Brigades, Divisions, and Corps.

Navy
The most distinctive feature of joining the Navy is obviously that you will be spending most of your time on the water. The nature of working on ships and watercraft almost guarantees a lot of travel. It also could mean time on specialized crafts like submarines or aircraft carriers, but it certainly means many long days without ever seeing land. The Navy also gives extensive educational grants and tuition reimbursements.

Air Force
Like the Navy, the Air Force is unique because of the primary area it covers - the skies. The Air Force members have a deep focus in technology, strategic attacks and air patrols. For many of the “glamour” jobs (a la Top Gun) in the Air Force, more extensive training and education is required. The Air Force is organized in Flights, Squadrons, Groups, Wings, Numbered Air Forces, and Major Commands.

Marine Corps
The Marine Corps is the only branch whose primary mission includes land, sea and air.  Special placements that only marines occupy include protecting current and former presidents, U.S. embassies around the world, and nuclear sites or providing emergency disaster relief around the world. The marines respond directly to the President (rather than congress as the other branches do). The Marine Corps is organized in Teams, Squads, Platoons, Companies, Regiments, and Divisions.

Coast Guard
The US Coast Guard is very different from other military service branches. You stay in the U.S. and act as our part of our coastal defense. You are also more likely to have day-to-day interactions with the civilian populations. In fact most of the lives you will be saving (and a huge part of the Coast Guard is saving individual lives!) are civilians. Because this is one of the smallest services it is very family oriented and there is a lot of room for advancement.

National Guard
The National Guard is generally our domestic protectors. They are there to keep the peace here in the U.S. and to control any national emergencies which occur. During wartime, however, they become a mobile force much like the other branches of service and can be deployed anywhere in the world. The Army National Guard maintains a relationship with the U.S. Army and the Air National Guard with the Air Force.

ROTC (Reserve Officer Training)
ROTC is an elective curriculum you take along with your required college classes. Generally, you would attend two training weekends a month and two full weeks of training per year. The ROTC program pays for your tuition (or a good portion of it) while you study at the college or university of your choice. Upon graduation you become an officer in one of the branches of the U.S. military (each branch has its own ROTC program which you will have to choose before you enroll).

To best decide which placement is best for your personality and interests talk to recruiters from all the different branches.  Here are some of the different types of service within each branch (From www.usmilitary.com):

Enlisted Personnel

Enlisted personnel begin at the lowest rank in the military and serve as the main workforce. The military prefers candidates with a high school education. With time, good service, and education, advancement can be expected.

Officers

Officers begin at a supervisory rank. They must have a four-year college degree from an accredited institution before being commissioned; however, the military has several programs that lead to becoming a commissioned officer: Military Academies, Officer Candidate Schools, ROTC, Direct Appointments

Regular Service

In the regular service, personnel serve on a full-time basis. After enlisting in the service, members are sent to basic training. Post graduation, they are sent to specialty job training schools. Upon completion, they are assigned to a station or unit for duty. After 20 years of regular service, members qualify for a military retirement.

Reserve Service

The reserves are part-time military soldiers. Personnel serve an initial period on active duty after attending basic training and job training. After the training period, which usually lasts several months, reservists are free to return to civilian life. However, for the remainder of the service obligation they attend training sessions and perform work in the job specialty one or two days a month with their local unit. Once a year, reservists participate in an active-duty training session for 14 days. When reservists have completed 20 years of service and have reached age 60, they are entitled to retirement, based on reserve pay.