This bill modifies federal military retirement rules for reserve component members who previously served on active duty. Specifically, it allows certain prior active duty service to count toward eligibility for an earlier retirement age when serving in the reserve components, such as the Army Reserve or Navy Reserve. The change applies retroactively to active duty service performed after January 28, 2008, meaning service members who served during that period may become newly eligible for benefits under this rule. The bill does not specify new funding requirements, as it primarily adjusts eligibility calculations for existing military retirement benefits. The legislation aims to recognize and reward military service by allowing reserve members with prior active duty experience to retire sooner than current rules permit.