This paper presents and discusses a longitudinal study which investigated habituation effects between humans and robots over a period of five weeks. Participants' preferences for the robot's approach distance with respect to its approach direction and appearance were investigated in a variety of domestic scenarios. These human-robot interaction (HRI) scenarios were also designed to explore the notions of autonomy and control. The results of this study show that participants' preferences change over time as the participants habituate to the robot. This trend was significant in terms of the robot's appearance and approach direction. Also, it seems to indicate that participants who are accustomed to the robot prefer to be more 'in control' of the situation in that they appreciated reduced robot autonomy in case of unexpected events.