Is regretting half the battle won?

If you can regret over something that will repeat itself, is it half the battle won?

Let's say you did very badly for an exam. You regret deeply about it. You know it was because you have not put in enough effort. You promised yourself that you'll put in more effort in the next semester, and that you'll not wait till the last hour to do your revisions.

Say that you did prepare hard the next time around and get rewarded with good grades. So we can say that the battle is won.

But say, what if it was the opposite. you repeated history in the next exam. Bad effort cause poor grades and you regret again.

Some people never regret anything in their lives. If they perform badly in an exam, they'll just tell themselves to move on and not look back. They never ever regret having poor grades. To those of them who managed to improve and attain good grades the next time around, we can say the battle is won. But what about those of them that never improve?

Can we then say that those that never improved but had regretted had therefore won half the battle, since they know what should have been done but had not been done versus those that don't even want to think about their failures?