A framework for understanding the tectonothermal evolution of solid planetary bodies has historically been lacking owing to sparse observational constraints. Developments in simulating the physical interiors and tectonic behaviour of terrestrial planets have allowed insights into the relevant physics and important factors governing planetary behaviour. This contribution summarises the critical factors in determining a planet's tectonic regime, and the application of this framework to understanding terrestrial planet evolution. Advances in modelling have led to the identification of new, unmapped tectonic regimes, such as episodic convection, which has relevance to our understanding of the evolution of the early Earth, Venus and Saturn's moon Enceladus. Coupling of tectonic and atmospheric models for planetary evolution has contributed to our knowledge of Martian and Venusian degassing histories, and recent debate on the tectonic regime of exosolar planets informs outstanding questions on their habitabilit...