My cofounder and I never seem to agree about what constitutes being "done"

The redesign shipped last week. He thought we were done when the UI was in line with Figma. I thought we were done when the tickets regarding that flow stopped coming in. After arguing for two days straight, it occurred to us that we had never actually sat down and defined it, four years into working together.

How would you define “done” at your company? And how many places did you put that definition down on paper?