Mobility practices in everyday life are often highly routinised and resistant to change. But they can also change significantly over the life course, reflecting sudden ruptures linked to incisive life events and more gradual shifts related to changing societal and environmental conditions. Combining insights from practice-theoretical mobility studies and mobility biographies research, this paper critically examines the role of material, social and cultural elements in transforming routine mobility practices, focusing on car ownership and use across the life course. Drawing on mobility-biographical interviews with people who live in Munich (Germany) and who do not own a car, it reveals the complexity of both one-off and daily decisions that help to establish and routinise carless mobility practices, linking them to social and material conditions past and present. The paper also documents the role of environmental and climate-related arguments in the transition towards carlessness, alongside shifts in infrastructure, social and economic circumstances and mobility-related skills and meanings. It concludes with some recommendations for sustainable mobility policy that works with the dynamics of car ownership and use across the life course and that incorporates both social and material aspects underpinning people’s decision to give up their private car.