The use of mathematical modelling to support and interpretate the results of a research project has become an essential part of the engineering activities in an R&D company. As a consequence different approaches and tools have to be developed and used in order to achieve better understanding of the phenomena involved and correctly address the experimental and design activities. The availability of oversimplified or rigorous models, steady-state or dynamic simulation, numerical fluid dynamics or finite-element codes increase the number of tools to be chosen, depending on the scope of the research phase involved. Therefore the engineering group of an R&D company, developing the knowledge for using all these approaches, would be able to choose step by step the most appropriate to achieve the goal. An interesting and exhaustive example of this strategy, a research project on the development of Solid Oxide Fuel Cells (SOFC), will be used to illustrate such concepts.