One way to categorize waves is to say that there are longitudinal and transverse waves. In a transverse wave, particles of the medium are displaced in a direction perpendicular to the direction of energy transport. In a longitudinal wave, particles of the medium are displaced in a direction parallel to energy transport.
Seven plans allowed normal retirement within these ages. Six of them required at least 30 years of service for normal retirement. Only two of the plans continue to allow normal retirement within these ages. Both now require a minimum age of 57 and at least 30 years of service. For most plans the minimum age requirement increased to the range of age 60 to age 62. Age 60.
There are some key differences between active duty and reserve component retirement benefits that must be understood in order to adequately plan for retirement; most importantly, the age at which you will be eligible to draw payments, which is generally age 60. There are also some differences in how the years of qualifying service are determined.