Equilibrium is a central concept in geomorphology. Despite file widespread use of the term, there is a great deal of variability in the ways equilibrium is portrayed and informs practice. Thus, there is confusion concerning the precise meanings and usage of the concept. In this chapter we draw on examples from dryland environments to investigate the practical implications of applying and testing the concept of equilibrium. Issues that we cover include the importance of scale and spatial variability, time, the assumption of constant environmental feedbacks and nonlinearities. The evaluation demonstrates that there are a range of problems inherent with using ideas of geomorphological equilibrium explicitly or implicitly to structure research in drylands. Many of these problems also apply to other environments.