Using grounded theory methodology, members of nine families with 'young carers' were interviewed to explore their experiences of caring. A dynamic theory of change and adaptation emerged in relation to changes in who cares within families, in external support and in the attitudes of young carers towards caring. Adaptations included becoming used to the way life is, knowing how to care, balancing and trading off, rewarding care, and anticipating future adaptations. A model has been developed to offer an explanation of factors which influence young caring in families. These include family expectations about caring; who is available to care; the willingness and capability of young carers to help; and the degree of choice or obligation they experience. Formal and informal support services from outside the family, and environmental adaptations, can reduce the amount of family caregiving required, increase choice and contribute to balancing life for carers.