Application of metal oxide arresters is essential for surge protection and safe operation of power systems. This presentation will outline how targeted use of these devices and taking insulation coordination into account can permit lower insulation levels than usual on individual components. It will also explain how lower insulation levels can lead to cost improvement or open the door to new applications of existing designs. Similarly, it will show that tailor-made high cooling arresters provide outstanding low protection levels and can contribute to reducing the number of thyristors in series in converter stations, helping drive down costs for HVDC transmission.