Continuous technical progress requires increasingly complex development processes. The trend towards resource-efficient products, for example, demands ever more complex designs while at the same time minimizing the use of raw materials. Optimization steps also require the most accurate predictions possible in all phases of the development process. High cost pressure and the aim of keeping development cycles as short as possible result in the need for high-precision and ever faster prediction tools. Numerical simulation methods are generally an attractive tool for dealing with these challenges. At the same time, the constantly increasing computing power raises the hope that the requirements can be met without restriction. Unfortunately, this hope often does not correspond to reality. In particular, the simulation of dynamic (transient) processes can currently only benefit to a limited extent from the increase in computing power. The reasons for these limitations and the space-time approach as a way of overcoming such limitations are presented below. Two application cases from the field of free-surface flow are intended to demonstrate the basic applicability of the methods discussed.