Basically, the parts on the mesh that deform more when moving around after being rigged are the ones that should have some extra polygons around them to prevent deforming.
Mario's model from Super Mario 3D world provides this in a very simple form. Though, there isn't space behind is knee for when his leg bends, making it look sorta awkward when bent all the way. You can also notice the same principle being applied to his belly.
Judging by the overall polygon count of his mesh, I doubt much of it was subsurfed. Or if any of it was at all. This is a great example of "less is more". As the mesh itself is very clean, and easy to make shape keys for, while they were optimized on extra polygons to make nice looking leg bends for animation purposes.
Mario's model from Super Mario 3D world provides this in a very simple form. Though, there isn't space behind is knee for when his leg bends, making it look sorta awkward when bent all the way. You can also notice the same principle being applied to his belly.
Judging by the overall polygon count of his mesh, I doubt much of it was subsurfed. Or if any of it was at all. This is a great example of "less is more". As the mesh itself is very clean, and easy to make shape keys for, while they were optimized on extra polygons to make nice looking leg bends for animation purposes.