A picture can be finished whenever you say.
Use the canvas for a little expression rather than a demand to fill every square.
Leave some blank space
An unfinished-looking edge or a quiet area can belong in the picture. The canvas has no completion percentage, score or competition asking you to keep painting.
Use Undo as part of creating
Trying a different colour is the activity, not a mistake to avoid. Change a square, compare the result and keep only what you like.
Save, then step away
Export a local SVG before closing or reloading when you want to keep the picture. Saving does not publish it or create a continuing obligation to return.
Share thoughtfully
Only send or share material you are comfortable disclosing. A control question needs a description of the tool, not sensitive personal information or access to your device.
A clear way back
Read the controls before returning, or leave the activity for another time.