Militaries often function as societies within societies, by having their own military communities, economies, education, medicine, and other aspects of a functioning civilian society. Although a 'military' is not limited to nations in of itself as many private military companies (or PMC's) can be used or 'hired' by organisations and figures as security, escort, or other means of protection; where police, agencies, or militaries are absent or not trusted.

There are different minimum AFQT score requirements for enlisting in the Army, Navy, Marines, Air Force, and Coast Guard, although requirements will vary depending upon whether you have a high school diploma or a GED. Minimum score requirements change on a fairly regular basis, with higher scores being required during times of above-average enlistment levels. Enlistment bonuses, which are determined by your choice of military occupation, may also be influenced by AFQT scores.
Again, the ASVAB is a wide-ranging exam covering many different areas. The designers of ASVAB practice tests, at least the high quality ones, know this and have spent time researching past tests to come up with practice tests that feature questions covering areas commonly tested for on the real exam. Thus, taking practice tests is a great way to focus on the material that matters most and avoid wasting your time studying content that likely won’t be on the test.
This advice, though well-intentioned, doesn’t address the needs of some new recruits who are interested in specific career fields but are worried about their test performance-especially in areas related to math comprehension. Potential recruits who feel deficient in math, language, or science skills should have a frank conversation with their recruiter to discuss possible refresher study or even supplemental classes in any self-perceived “problem areas” before taking the test.
A military recruiter determines if the candidate is a possible recruit. A recruiter will ask about marital status, health, education, drug use, and arrest record. It is important for the candidate to be upfront and truthful when answering questions. Once the recruiter has determined the individual is qualified for additional processing, the ASVAB is scheduled. A physical examination may also be conducted at the time of the test. 
The Student ASVAB is the most flexible of the exams. It is typically provided to high school students to help them assess their skills, job prospects, potential military positions, or college majors. The ASVAB for students is essentially the same as the MET ASVAB exam, only students are not necessarily testing for positions within the military. The students’ school counselors examine their scores and help them decide on what to do after graduating from high school. This test is still an important component of a student’s education because it can help them identify their strengths and weaknesses and help set them on the right track for their future career goals.