Thanks mate :)
I must admit it can be kind of a burden to add milestones during an ongoing work where we have to save specific steps.

That represents some more work charge after the moment we think we've done with the illustration itself and would want to take a breath.

But it's profitable to keep track of the process:
-for other people who may like to see the picture's building, that's a kind bonus gift.
-but also for the artist later, as a long term self-criticism resource.