If you want Excel do the job (of calculating and working), there are several mandatory rules. In this session I will discuss the importance of some of these rules. The goal is to create a logical process beginning with the input and ending at the output. The bottom line will be Excel models, which are effortless in use and will keep you – as designer / builder – always in control. If you invest more time (and thoughts) about the model you are about to make, in the end the more profits you benefit while working with that model.