You should review your Official Personnel Folder (OPF) to make sure that there is verification of all of your military and civilian service. If any of the records are missing, your employer should help you document the service and obtain any missing records.
If you have civilian service for which you must pay retirement contributions or repay a refund of contributions, your employer should tell you about what impact payment or non-payment has on your eligibility and the amount of your retirement benefit.
If you owe a payment to receive credit for military service you performed after 1956, you must make that payment before you retire. If you are receiving military retired pay, you should discuss whether or not you must waive the retired pay with the personnel officer at your agency.
Your personnel officer can also tell you about receiving credit in your annuity computation for various types of service and about the payments described above, as well as help you with service documentation.