Computers can support life cycle management in different ways. Normally, personal computer software in this field like Gabi, Simapro or Umberto are characterised as stand-alone solutions. They are normally not integrated into the computer-based information systems infrastructure of corporations. It would be better to have a fully integrated module within standard enterprise resource planning systems to provide decision support in the field of life cycle management. The question is why the stand-alone software tools are successful while still no software modules for enterprise resource systems are available. This paper examines the reasons for the success of computer tools today. Therefore, the first two chapters take a critical look at the theoretical background of instruments in the field of life cycle management, mainly life cycle assessment (LCA): the assumption that the instruments are decision support instruments.