This thesis looks at what being sustainable might mean, or entail, on different levels for a small milieu of activists on the new left in Ireland and the UK. I gather personal experiences of burn-out, care (collective-care and self-care), support structures and identity in social movements, to try and figure out what people have learned about sustainability through their lived experiences, tacit knowledge, workshops on the subjects and peoples varied communications on the often 'en vogue' term. The findings, as to what adds to an individuals or collectives sustainability and who does that framework of sustainability represent, are complex and contextual. Many activists cite a lack of awareness; personally and collectively, of motivations around activism and the 'prefect standard' synonymous with much activist work. For many there's a lack of an understanding of the normalisation of certain ways of organising and the dominant political paradigm of the new left which leaves activist circles open to repeating negative patterns and often inhibiting their own growth and progression. There is a self-defeating idea of what care means which often leaves people feeling unfulfilled. The oft complex nature of what 'good' change means is addressed throughout where we face seemingly contradictory situations, opinions and ideas. For example, participants talk about simultaneous positive and negative elements wrapped up in some practices, making them at once sustainable and unsustainable. If the new left is to move forward with others, in solidarity, then an understanding of the complexities and contradictions of how individuals and groups function (or don't function) needs to be developed, collectively. Through this study I attempt to confront the lack of vision I see in this area on the new left in Ireland, and in general, by compiling specific experiences and highlighting the needs of the participants. I finish with suggestions of what might be done next coming from the research and my own reflections.