A Maintenance kit is a preventive measure for HP Laser Jet series printers. Through extensive testing, HP engineers have determined that certain printer parts undergo similar wear patterns over time. The HP Laser Jet maintenance kit contains replacements for these parts. Although purchasing a maintenance kit is not required, regular insertion of a genuine HP Maintenance kit in an HP Laser Jet printer helps eliminate repeat service calls & maximizes paper feed & print quality performance. In addition, maintenance kits are priced substantially lower than purchasing these same parts individually.