Developing and implementing customized IT systems can be frustrating to both the developers and the users. From comprehensive observations made from three case studies of Swedish firms involved in developing and implementing ERP systems, certain reflections might be made that suggest that system development tends to occur by a series of sequential projects. This article develops some background necessary to understand the complexity that tends to arise in these projects. An illustration is given from an example obtained from the field, which reflects the observations made from classical literature on adoption processes and decision-making.