Cooking is a bit like art - there are many different styles and almost endless possibilities, a lot of effort goes into the end product - but at the end of the day what you serve up may not be to everyone's taste!
Now I can say to you, if you would only follow my recipes to the letter then you will be guaranteed a great dish, but maybe you don't want your food with as much pepper as I might, or you prefer it with more salt, less garlic etc
That's why the measurements in my recipes are guidelines only; so if you want to use 1 teaspoon of chili powder in your recipe instead of the 1/2 teaspoon that I put, then I say go for it!
If you are cooking regularly then you will cook on instinct anyway. I put measurements in my recipes for 1 tablespoon of this, or 1 teaspoon of that, but in reality, I very rarely actually use teaspoons and tablespoons for measuring ingredients. If you are tasting your dish as you go then you automatically know if it needs a bit