Thumbnails. Basically scribbles, legible only to me. I do a lot of these. Nobody sees them besides me.
Storytelling pose test. I don't fiddle with the timing, but I do view it at a low fps to get a sense of things. I use this pass to find out if my idea is working.
Keys, roughly timed out. Point of no return. I don't go past here unless I can commit to this pass.
Straight ahead animation. Keep it loose and iterate. I tweak my timing like a lunatic here. I think I could save time and do fewer inbetweens, leaving some of that for the cleanup pass - but it's nice to have as much information as possible. I think I always like this pass better than my cleanup :C
Cleanup - Don't have the file for this one, but I lower the opacity of the roughs until I can just barely see them, then do finished drawings on top of all my key poses. Because I was under a deadline for this, I went in and symbolized body parts that I could reuse (like the head), and made dynamic cycles for some of them. Then I go in frame by frame and match my roughs, toggling the layer visibility off and on to make sure I'm not losing the vitality of my roughs in cleanup.
As I'm sure you can tell, my process is pretty fluid and the passes definitely overlap each other at points! A lot of this workflow is straight lifted from Animators Survival Kit - I think having the logical underpinning of a keys and breakdowns pass with the spontaneity of straight ahead is the optimal win/win. Very similar to my CG process as well. Hope this was interesting to maybe two people!