May 04, 2022 21:42 Updated Follow There are several things that factor into the final cost of extra service. We suggest you read Buying Extra Service Credit if you are a member of PERF or TRF. For other funds, . Related articles I was a substitute teacher. How can I add this service to my account? How many years of creditable service must I have in order for my spouse or child to receive a survivor benefit from PERF? I was in the military. How can I add this service to my account? Do you accept credit cards? When should I start thinking about planning for retirement?