I know some the animators started using layered approach, I think it's really fast and efficient way to animate THEN why not using layers?
Our character rigs are really heavy and really hard to play in real time 24 fps unless hit playblast. I used to do that all the time, but think about how long we waste just waiting for letting computer do their jobs.
So I put everything in layers.
I put all the clothes, body and hands in a layer when I am working on facial. I put legs or any other body parts in a layer when they are not showing in the main camera. I hide Catherine when I am working on William. I usually make several layers depending on where I am working on then. so now I can play my shot by 24 fps(or at least look like). Of course, there are several situations that we can not avoid to deal with heavy stuff but at least I usually try to make it faster. Faster means I can try different ways more, and it means quality to me. Work efficiently, quality and sleep well.