This study explores the use of socially assistive robots (SARs) for behavioural coaching for healthy habit formation. We conducted four focus group discussions with nineteen end users to understand their needs and expectations for SAR coaches. We performed a thematic and narrative analysis of the data collected. Our findings emphasise the significance of SARs in assisting individuals and equipping them with the skills for independent health management after the intervention ends. The design requirements generated are centred around interaction, ethics, and environment and are justified by linking them with established behavioural theories. These requirements will help guide the development of robotic interventions that support long-term habit formation.