Karst systems play an important part in providing clean drinking water for many countries worldwide. Their sustainable management often requires the application of karst hydrological models to quantify the water volumes available and to assess their sensitivity to changes in climate or land use. The available literature provides a broad overview of different modelling approaches to simulate karst hydrology, but guidance for the application of these approaches is scarce. This paper provides personal insights into the application, calibration and evaluation of lumped karst hydrological models. An introduction to model calibration and sensitivity analysis is given, with links to further reading and ready-to-use toolboxes. It is followed by three case studies of karst model applications at three different scales (the plot scale, aquifer scale and continental scale), which apply model calibration and sensitivity analysis to obtain realistic simulations. These three case studies elaborate how the necessary trade-off between the available data and process representation in the model structures was achieved. General recommendations and a workflow for future karst model applications are given.