Continuum models were originally designed to handle liquid solution environments where the statistical averaging assumption in the relevant regions was viable. Typically these environments would have neutral net charge and a temperature where specific interactions like hydrogen bonding did not compromise the homogeneity of the system. These models have evolved to handle a wider variety of systems, such as ionic liquids and complex multiscale dielectric environments, such as metal nanoparticles and plasmonic devices on nearby QM systems.