This paper presents three CBR systems that have been developed over seven years in collaboration with two industrial partners. In this research, case based reasoning (CBR) is used to compute costs of construction projects. In contrast with previous work in the field of CBR, the focus is on choosing strategies that are compatible with user needs and characteristics. Comparing the three strategies reveals advantages and drawbacks while illustrating a "real-life" evolution of a CBR architecture in an industrial context. An important conclusion is that the ways users perform tasks have a direct influence on the best architecture for the CBR system (e.g. transformational/derivational analogy). Incremental development of strategies in the final system improves user interaction, expedites time consuming tasks and favours identification of synergy between techniques such as CBR and data mining. © 2007 Elsevier Ltd. All rights reserved.