You can always do better. But in most cases, 80% quality is enough.
I was asked a reasonable question: how to understand that you have reached these 80%?
If I write a post, then 80% of the quality comes when I conveyed my thought and structured the presentation in such a way that the reader can quickly grasp it. Detailed improvements and text embellishments will not improve the reader’s life. Can only make the reading a little more pleasant.
If I design an interface, then 80% of quality comes when the user can easily understand the essence of the product and do his job. Refinement of the visual and creation of wow-effects are secondary. The main thing is that the user can do what he came for.
Conclusion: 80% of quality occurs at the moment when the created product begins to fulfill its task. It follows from this that before starting any project, you need to define its task.
The remaining 20% can make the product more enjoyable to use, but chances are that it will take a lot of time and you just get bogged down in details. Better to start with 80% quality, and then bring the product to perfection. If need be.