They highlighted that in addition to assessment and treatment, non-attendance meant that clients missed the opportunity of being given lifestyle advice. This qualitative study revealed that whilst clients often gave simple explanations for non-attendance, such as forgetting or not being motivated to attend, the underlying reasons were far more complex. These findings have important implications for drug policy including the need to better understand and incorporate clients’ perspectives. It further has the potential to address health inequalities and has fostered strong partnerships with clients to develop a suite of resources.