Today, more and more problems, such as labor shortages, customer expectations, strict legal environment, and traffic jams, are challenging logistics service providers. Based on practical experience, a prerequisite for efficient distribution is the accurate routing. For this, however, it is essential to use accurate data. This chapter summarizes and presents the most important data needed for efficient routing and the accuracy classes of data. Then, through an example of a logistics service provider’s data, it details the required data and their typical accuracy. With this data and the widely used routing software Paragon, the results of the routing will be compared. Finally, this chapter summarizes the relationship between the accuracy of the data and the usability of the plans. On this basis, proposals for logistics service providers to support efficient operation are made.