What build would benefit most from the Durable feat? [closed]

The Durable feat includes the following benefit:

When you roll a Hit Die to regain hit points, the minimum number of hit points you regain from the roll equals twice your Constitution modifier (minimum of 2)

Which hit die / Constitution modifier combination would be effected most often when rolling hit dice?

What I have figured out.
So far, I have figured out that a Constitution of 12 or 13 would be the worst you could have, as the minimum of 2 would not effect you at all. Also, I think that with high Constitution, a low hit dice would be better, as you’d have a greater chance of rolling below your minimum, but I am not sure.

Note: Level 20 Barbarians with +6 or +7 Constitution modifiers can be included.