Rendering in Layers

Aminata mentioned to me to look into rendering in layers. We are thinking of using this rendering technique because for what we want to do it will save more time rendering such things like the animation,shadows of characters,background and possibly an occlusion pass seperately and then compositing them together again in after effects. I have looked at a tutorial on www.tutorialcentral.com on this process, and it seems to be quite straight foward.