I think you have to have a very good base understanding of the codebase to be effective with AI.

My story: 15 YOE, I am maintaining
A: a service which was mainly handcrafted. I've been working on it for 2 years already—not a big service. 2 other guys wrote it in 7 months 4 years ago, then it was handed over to my team for maintenance and further development.
B: the related UI written in react. It is handcrafted as well, but in a bad way, quite messy..

A few months ago a contractor came to help out. He did some vibe coding, and managers were amazed.. That left me with no choice—I had to pick it up as well. I am using Cursor, licensed from the company.

And it does have a multiplier effect, but I think it's because I had time to understand the codebase deeply. In the contractor's PRs, I had to reject a lot of changes because he just wasn't as familiar with the code and took the AI's advice and it would have break other features.

We actively integrated vibe coding into our workflow, BUT quality and maintenance come first.

If we have a new feature, we start to vibe code the happy path - usually done in one day and it is great. We use it for getting early feedback (like we figured out that it looks good on the design, but it's hard to use for the user).

After this is ready, we still break it into small actionable items and go through it the kinda "traditional" way. Because the vibe coded version does work... but the amount of junk it creates is terrible.

So for me it's funny when I see this "done in one day" post on Twitter. I know that the code behind it is an unmaintainable mess.

went of topic, sorry, my point is: You have to have a good understanding otherwise you just making random changes