I do sketches all the time. Often because I'm too lazy to do anything else, but mostly as a means of getting out an idea for something I want to elaborate on later. Examples:
When I get an idea for something, I usually draw out a little thumbnail sketch to get a basic idea of what I want to do. I do a
LOT of these. Here's a collage of a bunch that were all inspired by Acid Bath songs:
A few I've elaborated on. Such as this:
and:
Here's a few more sketches that I turned into more finished pieces:
I realize that these are kinda large, but it's 4:30 am and I'm too lazy to go back and re-size it all.