The Royal Library of Sweden (KB), which serves as the national library in Sweden, decided in November of 2008 to start using DDC instead of SAB. For a long time, SAB was used as the main classification system in Sweden across all types of libraries. The reasons for this decision were among others that it would help swedish libraries to become more interconnected with libraries in other european countries, who already use DDC. Another reason for the decision is that DDC already has a support network and regularly gets new editions and updates. But now all of the university libraries in Sweden have switched to DDC in some capacity, for either the entire or parts of the library's collection. Public libraries however mostly still use SAB for both their collections and classification. The purpose of this study, which takes place in the spring of 2021, is to examine librarians preferences and opinions about these two systems. Semi-structured qualitative interviews with a total of six librarians across four different academic libraries in Sweden, have been conducted to accomplish this. For this study, a number of psychological terms have been used as a theoretical framework to analyze the librarians opinions. These terms are: preferences, stability, trends and mere-exposure. The findings show that a majority of the librarians prefer SAB over DDC. Moreover they also considered that The Royal Library of Sweden made the correct decision to switch to DDC.