You can always remove the excess geometry...assuming you aren't modeling at high poly level (what's the point of subdividing if you are?). However, I agree that it improves the flow if you model everything fresh and I find it works best for all the features of the head.  The advice that you should look at the wires of others to learn how they do it, is GREAT! That's how I learned and eventually, things just start to make sense - in terms of the process.  Base meshes used for sculpting are especially useful to this end, as they are the bare bones starting point usually, without the excess polygons subdivision brings.