Industrial services such as classical MRO-services and also advanced offerings, e.g. performance based contracting, are gaining importance in the machine and equipment industry. From a niche the business units responsible for service have grown to major contributors to the success of the company. Meanwhile operations have grown historically and service manager struggle to professionalize their service operations to improve efficiency. In this contribution we provide an overview of 3 cases of companies trying to gain competitiveness by using a simulation-based decision support system for field service supply networks.