The overall cost to perform maintenance work includes internal resources, external resources, stock materials/tools, and externally procured materials. This represents the total cost of maintaining assets. External resources or services represents a large percentage of maintenance cost.
In SAP Plant Maintenance, there are several different options in how to configure and procure Maintenance Services. The below presentation conducted during the 2016 Annual ASUG meeting in Orlando FL, touched upon some of the options available today.