Based upon twenty unstructured interviews of social workers from Montreal surroundings, this paper analyzes the personalization of social intervention dealing with drug addiction, especially from a harm reduction point of view. Seeking to enable the individuals’ autonomy by establishing a relationship of trust, personalization is built on personal rhythms and goals. However in most cases, the obligation to support people in distress has to be tactfully balanced with the rejection of any kind of intrusion in personal lives. Thus, it becomes essential for social workers to distinguish timeframes when they have to intervene form those when it is better to hang back. Keeping the right distance is necessary not to break the relationship, and works as a two-way channel: physical proximity (where to stand and where not to), and verbal proximity (what to say and how to). This article discusses how this relationship is both created and maintained, what influence it has on the objectives of daily intervention, and the definition of its purposes by social workers.