When you start working from recipes, you tend to want to follow the recipe as precisely and completely as possible. Every 1/4 tsp. of salt, vanilla extract measured precisely, flour sifted exactly as directed.
Over time, you learn what should stay close to the recipe, and what can be adapted. The vanilla can be substituted, or left out, but clumped flour is going to give you problems. Salt and flour should probably retain their ratios, but if you like your breads a little sweeter (or with a little more whole grain), you can adapt those things easily enough.
Knowing what’s required and what’s suggested is a good step towards expertise as a home cook. It opens you up to variations and to understanding the underlying concepts to the recipes you attempt.
And of course, it’s the same in music. When you start, you try to follow everything in the score, as carefully as possible. Over time, hopefully, you learn what in the score is required, and what’s suggested.
Following recipes precisely is not the sign of an expert – it’s the sign of an avid student. But when you leave your study behind, you must learn to dig deeper into the score and rely on it less.