One of the most wide-reaching and significant changes to military pay and benefits over the last 70 years took effect Jan. 1, 2018, with the implementation of the Uniformed Services Blended Retirement System, known as BRS. Nearly 1.6 million current service members have the option to remain in the current legacy “high-3” retirement system or to choose the BRS. Opt-in eligible service members have a year to make their retirement system election. The open period for the majority of service members is from Jan. 1 through Dec. 31, 2018.