Based on empirical data on “green” practices according to household size, this article questions the role, if any, given to close personal relationships by social practice theories in sustaining or not daily life practices. Data are mainly drawn from an Internet survey conducted in Belgium in 2006 by WWF-Belgium on daily practices, related to food, energy consumption, mobility, and tourism. Results show that smaller households carry out more numerous “green” practices than larger ones. The concluding discussion underlines the relevance of including social interactions—namely within the household—into the conceptual framework derived from the social theories of practices, to take into account the rearticulating role of social interactions and domestic power claims when carrying out a practice or a set of practices, and when changing it.