Cultural heritage digital libraries have a range of users including professionals; "digital natives" as well as general users. Their motivation and needs differ and one of the challenges in evaluating how digital libraries are perceived is to understand the specific points of view of various communities. The identification of stumbling blocks and features which are not satisfying users’ expectations is aimed not only to develop a clearer understanding of users and to serve them better but also to sustain a steady user community. The paper addresses how user evaluations could help to adapt the digital libraries to the users. Three case studies will illustrate how a range of user communities within the art and cultural heritage domain were studied. The first one treats the user survey initiative held for the Italian Association of Librarians AIB portal, launched in the phase of its re-styling through a web questionnaire that collected more than 600 answers. The second, within the project DiSCmap, studied the needs in digitized materials within the Higher Education institutions in the UK. The third one assessed the European digital library Europeana through a combination of focus groups and media labs held in four countries. This study was qualitative but gathered a range of quantitative data providing evidence of user behaviour (queries used; eye tracking data and data on the users’ performance on a standard set of tasks). All those studies synthesized recommendations on the preferred characteristics and features of the digital libraries from the point of view of specific user communities. The paper will provide practical examples which illustrate how quantitative and qualitative elements in a user study help to build a better picture of the users’ needs.