Q: I can retire in February with 31 years of service under the Civil Service Retirement System as a part-time/flex employee in the U.S. Postal Service. My “high-3” years were from 2006-2009. Will they use these years to calculate my annuity? Is it always the last years? Is it always three consecutive years, or is it the highest consecutive three years? As a PTF, my hours changed yearly as to how many offices I worked in. Also, when I was hired in 1979, I never heard of “buying back” or anything related. Since I made no deposits, or didn’t know…