This is one of those spots where I think that Scrum gets things right. Having the ticket priority ultimately belong to a single person (the product owner) sets up a pretty decent incentive structure. It makes it easy for that person to figure out on their own exactly how precise they need to be, and where the precision is needed, in order to get their job done.
When I see over-polishing happening in the wild, it tends to be in response to "too many cooks in the kitchen" type situations. Well, that or procrastination.
When I see over-polishing happening in the wild, it tends to be in response to "too many cooks in the kitchen" type situations. Well, that or procrastination.