So, my current rules of energy and work seem to be:
When I'm well-rested and energized, I write.
When I'm moderately well-rested and feeling okayish, I design.
When I'm feeling tired and a bit dumb, I do graphics (mapping, page layout, etc).
When I'm feeling utterly wiped out, I work on fonts.
When I'm feeling too sleepy and stupid to do fonts, I endlessly tweak the wording in Applesauce. 😅