The world's population continues to grow. With a trend of urbanisation apparent, increasing attention is now being given to understanding and shaping our cities to support an evolving society. Urban metabolism concerns the flows of material and non-material resources and wastes that characterise the functioning and sustainability of a city and which are fundamentally associated with human behaviour. This paper centres upon an examination of how the digital age is supporting and contributing to changing lifestyles and more particularly lifestyle expression. It shines a light on how a rapidly evolving telecommunications system is influencing, and has future potential to influence, how we participate in society with resultant consequences for urban stocks and flows. In particular, the paper considers the integration of digital technologies into everyday life (digitalization) and their influence both spatially and temporally on our engagement in working, leisure and shopping. It also considers the phenomenon of collaborative consumption in cities (whereby sharing of goods and services, facilitated by digitalization, creates yet further dynamics for urban metabolism). The paper reveals the highly complex and evolving nature of digitalization and collaborative consumption and associated challenges in defining, measuring and understanding the dynamics of human behaviour and social and business practices. In response to this it also considers the underpinning driver of urban metabolism -fulfilment of society's need or desire to access people, goods, services and opportunities. The paper outlines how different paths of urban development are now shaped by the inter-play between our land-use, transport and telecommunications systems and their use in terms of accessibility. Considerations for research and policymaking are highlighted which include the importance of addressing methodological issues in the face of a changing and uncertain future.2