All Branches

• All military branches require you to sign up for eight years of service. Whether they are all performed in active duty or not, you are still committing yourself to eight years in the armed forces. Although you may be breaking up the time between active duty and reserves, you have still signed up for at least eight years. You can continue past those eight years and make the military your career. If you re-sign after your original eight years, it is possible to sign up for a shorter duration than another eight years. After reaching 20 years of service, enlisted military or officers may retire.
  
  

Individual Ready Reserves and Drilling Guard Reserves

• Once you have completed your active-duty commitment, you generally go into the Individual Ready Reserves (IRR). During this time, you do not drill, train or receive pay. You are able to take another job. You name does stay on a list, however, to be called back to active duty if the need arises, until your eight years are completed. You may also go into Drilling Guard Reserves, which requires you to drill one weekend each month and two weeks per year. You are paid for the time you are drilling, and you are still able to hold a separate job, since employers have to allow you to leave for drilling. It is more of a time commitment than the IRR.
  
  

Army Breakdown

• In the Army, you may sign up for anywhere between two and five years of active duty, while finishing up your eight year commitment in the Army reserves. While in the reserves, however, you are available to be called back into active duty at any moment. This is especially important to keep in mind if the US is at war.
  
  

Navy Breakdown

• The U.S. Navy will allow people to enlist for two years of active duty. You must also commit to two to four years of active drilling reserves. If you sign up for two years of active and two years of drilling reserves, you are then able to take the remaining four years as IRR.
  
  

Marines, Air Force, Coast Guard

• The U.S. Marines, Air Force and Coast Guard require a minimum active duty enlistment sign-up of four years. After those four years are up, enlisted military can go on IRR or Active Drilling Reserves. Again, it is important to remember that you may be called up at any time during your reserve years to go back to active duty.