Analyses on the limits of EU internal market law mainly focus on substantive evolutions regarding the underlying concepts. However, once the European Court of Justice (ECJ) has clarified the scope of the free movement principles, the ball is then passed to the national judiciary. In the future application of these boundaries, the judicial dialogue remains crucial to ensure an effective and correct implementation of EU law. This interaction is based on a set of procedural guidelines. Whereas such rules might appear as fixed circumstances, this article will demonstrate how the ECJ – through different dynamics – ensures the correct interaction between substantive and procedural evolutions. This ‘procedural customization’ will be uncovered regarding two central limits of EU internal market law: de minimis thresholds, and the purely internal situation doctrine.