Many products have become more and more complex and tailor-made. Consequently, product data is an extremely important factor to ensure the success and the sustainability of a product. Large and complex products, systems or facilities were managed in the past without the enhanced information technology systems available nowadays. Among some successful products or systems, one can cite space programs such as the NASA Apollo program or the particle accelerators built as from the 1950s such as that of CERN, Geneva, Switzerland, which serves as a case study for this paper. Some of the products developed in these eras are still in operation. Projects and practitioner approaches were developed and are still under development to address the problem of migrating data, produced with different technologies, to today’s technologies. For instance, the ISO 10303 standard—also known as the STEP standard (Standard for the Exchange of Product Data)—provides the means to transfer CAD data between systems. But only little attention has been drawn to providing reliable means for integrating the information from different lifecycle phases together. This paper aims to draw attention to the issues raised by the use of different terminologies and systems in different lifecycle phases, in particular the concept of item during conception and development phase, and the concept of asset during that of operations and maintenance and some problems that this may bring.