Density at Key Areas for Corrective Blend Shapes and Volume Preservation
A common issue when dealing with high bend areas, like the elbow/knee/shoulder/hip, is that no matter how it's constructed or weighted, a corrective blend shape or additional helper joints will eventually be needed to create a more pleasing result.
Using the knee as prime example, you can see the difference in these two legs (Fig.04).
Fig.04 - Density in high blend areas
The leg built for even spans does not have much density to work with to sculpt out a corrective shape for a bent knee (harder edge, 90 degree point and defined knee cap). Whereas the more anatomical leg was created with deformation in mind, leaving enough spans in the mesh to allow a corrective shape.
Finger and Knuckles
Depending on the medium, finger layout can change drastically. From trying to save edge loops for games (Fig.05).