A complex product system consists of numerous subsystems organized in a hierarchical fashion. In literature there exists a tendency in measuring the life cycle of main system by using parameters which characterize the performance of that main technology. This may lead to problems in investment decisions for technology renewal since the forecast of main system technology lifecycle is associated but does not fully represent its subsystems lifecycle. This paper intends to clarify this problem with a case study by showing while the main system is in its midlife; some of the subsystems are approaching their limits and requires urgent radical investment. As a case study refrigerator system is used and the relevant life cycles are obtained using growth curves as a technology forecasting tool. The findings are discussed and suggestions for the need of a multiple level of analysis are given in the discussion section.