It was a good lecture. I've rarely seen refactoring and OOP design applied in practice, but it was great to be able to practice them directly through the examples in each lecture. Lectures on the clean-coders website cost about $12 each, but seeing the instructor explain things easily in Korean and show the entire process of refactoring examples helped me identify areas where I was lacking. Just listening to this entire lecture won't make magic happen. I believe that if you reflect on what you need and practice it yourself, it will help you achieve better design, testing, and refactoring. One drawback is that since it's a free lecture, finding the examples isn't easy. In the latter half, I had to find them directly by looking at the repository names, but I studied thinking I had to endure that to watch such a good lecture. Thank you for sharing a lecture that, despite being 10 years old, is still valid today. For someone living in the provinces, it was a lifesaver.