Where's the fiberglass? and insulation?

Does anyone have any thoughts on fiberglassing the exterior walls and roofs of our babies? There seems to be a curious absence of the material within this forum. Why? Just not worth the effort?
Also, I see everybody putting great effort and thicknesses of insulation in the ceilings but not much on the side walls... why is that?
Respectfully,

Also, I see everybody putting great effort and thicknesses of insulation in the ceilings but not much on the side walls... why is that?
Respectfully,
