For the efficient design, installation, operation and maintenance of a plant, a reliable and robust mathematical model for predicting corrosion in pipelines can be a valuable asset. Such a model can help a plant supervisor to cut down on the expenditure arising from frequent inspections and unnecessary maintenance shutdowns and to take preventive maintenance action before an accident actually takes place. This paper discusses some of the philosophical issues related to the development of such a model. It also brings to the fore the limitations and value of such a model.