Although the life-course perspective emphasizes the importance of the concept of social norms for understanding demographic choices, the usefulness of this concept is heavily debated. In particular, it has been questioned whether social norms are still important in post-modern societies, and whether societal expectations can really be called norms if no sanctions are attached to them. In this article, we review the theoretical and empirical literature, highlight the potential usefulness of the concept, and illustrate its importance by presenting empirical data on the existence of norms concerning demographic choices in The Netherlands, one of the most individualized countries in the world.