I have a tendency to redraw panels way too often. Usually it leads to better panels but also a lot less time to finish the whole page.
Here's one example of a re-draw (I deleted the first lineart, so there's only the sketch version left):


Basically the panel was boring. No drama, no action, just plain and boring! It took me forever to re-draw it but I'm really happy I did. Boring panels are the most common reason for my re-draws but I also re-draw them when they just look wrong in some way.