Concurrent finite temperature atomistic-to-continuum models commonly use a fixed time interval coupling of the atomistic and continuum scale. With special focus on the continuum, this means, that its solution fields are updated in fixed intervals of time. However, in times, when the change in the continuum boundary conditions is negligible, these computations are unnecessary. We present the novel idea of a demand-based coupling in this work, in which the continuum solution fields are only updated if needed, to save computational effort. To demonstrate the approach, we apply the coupling to a prototypical representative of the mentioned models, namely the coupled atomistic and discrete dislocation (CADD) model. We test the basic functionality of the approach in a 1-dimensional pulse propagation problem.