Abstract
Work orders for 40 tractors collected by Hail Agricultural Development Company, Saudi Arabia, were used in this study. Data for more than 1670 work orders were classified as repairs or maintenance and the relationship between tractor age and power on repair and maintenance costs was investigated. Fifty-one percent of the work orders were classified as repair work while 49% were maintenance. Repair mean total costs were significantly higher than maintenance costs. Repair and maintenance mean total costs were directly related to tractor working life (age) and tractor power.