To retire you must meet two requirements: age and service credit . Your minimum retirement age depends on your retirement formula: 50, 52, or 55 .The County of Riverside offers a voluntary Deferred Compensation Plan to assist employees in meeting their financial goals in retirement. Retirement Requirements. Employees must meet the following requirements to be eligible for retirement under the Federal Employees Retirement System (FERS). District Fiscal Services provides payroll and retirement processing services to LEAs in Riverside County. The following chart outlines the requirements for an immediate annuity under the Federal Employees. Retirement System (FERS). 137 What is the Federal. Employee Retirement.