Complex systems are the backbone of modern industrial societies. They include critical infrastructures such as energy, communications, logistics, manufacturing and early warning systems. The aim of the study is to shed light on the risks of failure and resource requirements of complex technical systems using critical infrastructures as an example. The aim is to identify system characteristics and elements that pose a particular risk as complexity increases, as well as related precautions or measures that help to minimise these risks. Furthermore, it will be analysed which warning signals can indicate the imminent overload or risk of disruption of complex systems.