In my school district, school nurses belong to the same retirement program as teachers. California State Teachers Retirement System (CALSTRS) requires five service credits for a teacher to become vested and eligible to receive lifelong annuities upon retirement. A teacher earns a service credit for every full school term he/she works. Service credits are prorated accordingly for shorter teaching contracts. The formula to calculate your retirement is based on age, service credit, and salary while working. Working in another state does not affect the benefits you have already accrued. When you leave the state, you may elect to leave your money in CALSTRS until you reach retirement age or get a refund. If you leave your money in CALSTRS, your benefit amount will only increase with age (up to age 63). The final amount of your monthly benefit will not increase based on service credits and increased salary. In addition, once you withdraw money from a CALSTRS account, you have to pay taxes.