In my teams, I try to pre-empt as much as possible by getting feedback from users on mockups. And then the item is "done", only when product verifies the core flows before it goes to production. I don't do Scrum/sprints (I think it puts artificial timelines and unnatural item splits) , but more aligned with Kanban (this gives me never-ending grief about quarterly releases, QBRs etc, but thats another story). So we try to make what's "done" fairly well defined. Does this slow down shipping? A little bit. But in practice, we end up shipping something at least a couple times a week.

We used to play a bit fast-and-loose with what's defined as "done", and that allowed us to ship everyday, but the loose part of that invariably came back from our customers, at a much higher cost. So we went back to being a little more rigorous.