 While in the Army Reserve, soldiers may belong to the active Army Reserve, or the Individual Ready Reserve.The key difference is that active Army Reserve soldiers typically attend Battle Assembly one weekend a month, twelve months a year, and also attend a statutory two-week period of active duty every year, referred to as Annual Training.Conversely, members of the Individual Ready Reserve are not required to attend Battle Assembly or Annual Training, but remain committed to military service obligations and may be recalled to active duty as directed by the President or U.S. Congress.