The use of new assistive technologies in general, and Socially Assistive Robots (SAR) in particular is becoming increasingly common for supporting people’s health and well-being. However, it still faces many issues regarding long-term adherence, acceptability and utility. Most of these issues are due to design processes that insufficiently take into account the needs, preferences and values of intended users. Other issues are related to the currently very limited amount of long-term evaluations, performed in real world settings, for SAR. This study presents the results of two regional projects that consider as a starting hypothesis that the assessment in controlled environments and/or with short exposures may not be enough in the design of a SAR deployed in a retirement home and the necessity of designing for and with users. Thus, the proposed methodology has focused in use cases definitions that follow a human-centred and participatory design approach. The main goals have been facilitating system acceptance and attachment by involving stakeholders in the robots design and evaluation, overcoming usage barriers and considering user’s needs integration. The implementation of the first use case deployed and the two-phase pilot test performed in the retirement home are presented. In particular, a detailed description of the interface re-design process based on improving a basic prototype with users’ feedback and recommendations is presented together with main results of a formal evaluation that has highlighted the impact of changes and improvements addressed in the first redesign loop of the system.