Before the 2009 decision in Callow v Rupchev, there were three circumstances in which an occupation fee would be payable by a co-owner to another co-owner. In Callow v Rupchev the NSW Court of Appeal found a further circumstance in which occupation rent can be claimed — cases of relationship breakdown where there is no 'attributable fault' by either party. This further ground is to be distinguished from actual ouster and constructive ouster. This article explores the context in which this decision was made, and reviews previous decisions relating to claims for occupation rent occurring within a relationship breakdown. To the extent that the doctrine of ouster has traditionally represented a particular understanding of the nature of an undivided proprietary interest inland, this article assesses whether this approach flags a transition in our understanding of the concept of property to mirror a more contemporary picture of society.