One reason polygroups are so helpful during modeling is they allow to quickly isolate an area of the model. This is helpful for working on one area while not affecting other areas. Its also possible to isolate an area while gradually moving into another area.
Today i used polygroups to help prepare a bear model i was working on in an arms and legs stretched out position. Then i did a zremesher to reduce the polycount and allow the smooth brush to have an affect. I used zremesher guide brush to make loops on shoulder and hips. I later used these same polygroups to help smooth areas separately. Here are some preliminary results. I plan on eventually creating deformations for this model.
Below is a more detailed walk through on an original design and model of an elephant (the back legs still need a bit of topology work):
Another slight tip for getting a front and side drawing of model lined up quickly is to use the grid lines in Maya then switch between front and side camera taking a picture of the model. I'll probably redesign this to make it more animation friendly (reduction of unnecessary polys) and appealing.