I usually have about 30 to 50 layers, but I group them up.
This one took about 10 layers or so.
While this one took more or less 40-50 layers.
I usually sketch the pages on a sketchbook and then lineart them on PS. The thing is, I didn't know that the actual sketch picture is about 50mb. which lagged the software, so bad. I didn't notice this until I drew the first picture I sent, which is page 19. by that time, I've already linearted and colored most pages.
Other than that, I've had no problem with my comic layers layout 