for topology in general I often look into these criterial and try to find the best balance, not order by important :
A- ability to follow loop / edge flow that can support all 4 of the following:
+ 1 - Animation Support Deformation flow,
+ 2 - UV seam , bodypart seam.
+ 3 - Anatomy detail edge flow
+ 4 - Articular ( Anatomy edges flow vs Animation flow )
B- simplicity ( not too overcomplicated ) while maintain all the A criterials
C- flexibility in increase/decrease tris-count while maintain all first 2 points.
But most of the time I spent most of my time refining the B points over the year, it's really hard for me as far as anatomy correct vs articular topology flow goes. ( even harder when everything is skinned and put into motion to test ) But I have developed some methodology myself over time to overcome these little by little , I think I would make a small tutorial if I have time in the future.