In the light of new information it is sometimes necessary to change existing beliefs regarding the state of the world. During such a belief revision reasoners have to decide which beliefs to retain and which ones to retract in order to regain consistency within their belief states. Drawn from the conception that spatial belief revision is based on the alteration of mental models, we discuss the influence of cognitive effort and minimal change when constructing and revising mental models. We offer several possibilities how minimal change can be defined in this context and provide a computational model along with a cost function to describe the revision processes. Furthermore, we present empirical evidence for the suitability of the model. Results indicate that there is a significant influence of cognitive efficiency principles on spatial belief revision.