Small studies are yoga for the brain
At only 3 inches square, I can't make the "I don't have time for that" excuse. So even if an image takes me several hours over many days to complete, it's still a fraction of the time a large scale image would take.
The constraint of working small also forces me to focus on only the most important details. Maybe I work on accurately capturing shape or spacing. Sometimes I celebrate color. I try not to much time planning; not planning something to death is a lesson in itself.
Few of my Threebys are worthy of public viewing- they're exercises, not the main event. You can find them scattered around my studio, in the bottoms of drawers, wedged in-between pots of gesso and GAC. Most hit the circular file after spending a few weeks bouncing around my desktop.