If your age plus your years of eligible service credit equal 80, you can retire under the "Rule of. 80. Employees are vested after eight years of service.If you began work on or after Sept. Vested members must apply for a service retirement benefit in order to receive a pension. The largest worldwide survey of government employees that annually tracks how employees view workforce management, policies, and new initiatives. Benefits-eligible employees also participate in a mandatory retirement plan and have access to a voluntary retirement savings program as well. Use this set of interactive worksheets from the Department of Labor to plan for retirement. They can help you manage your finances and begin your savings plan. If you have not reached your 20 years covered Law Enforcement or Fire Fighter service and reach the age 57, you must retire in the month you reach your 20 years. Tarrant County is part of the Texas County and District Retirement System (TCDRS).