Airman 1st Class Dillion Rickman, 28th Logistics Readiness Squadron vehicle and vehicular equipment mechanic, uses an oil pump during an oil change in the vehicle maintenance shop at Ellsworth Air Force Base, S.D., April 24, 2012. Routine oil changes are required approximately every 3,000 miles to ensure that all the government vehicles on base stay operationally ready. (U.S. Air Force photo by Airman 1st Class Kate Thornton/Released)