The Agenda 21 model consists of economic, social, and ecological considerations, which are to be balanced for the sustainability concept to be applicable. However, the model is silent on how value conflicts within and between each sphere is handled. These conflicts are investigated in connection with temporal and place dimensions in the three spheres. Anecdotal empirical evidence indicates that three spheres are insufficient and that cultural heritage should be added. Models of sustainability should explicitly address issues of conservation and utilisation value. An attempt is made to integrate all these qualities into an integrated model.