Modelers strive for “clean” topology, typically illustrated by a 3D mesh with efficient polygon distribution, proper placement of polygonal edge-loops, few or no triangular faces (as opposed to 4-sided “quads”), and clean precise creases that minimize stretching and distortion.

The second aspect of good topology, and an important concept when modeling for animation is increased polygonal resolution in areas of a 3D model that will undergo the most deformation during animation (joints, facial features, moving parts). (Source: lifewire.com)