Gulp is smart enough to only compile the files that it needs to compile. This means that if you change some Sass inside a component, Gulp will only compile the CSS of that component and not recompile the CSS of every component. This makes the compilation process lightning fast.

If you are wondering about when to write Sass component-specific and when to write theme-specific, please check the chapter on component.scss

The Gulp is packed with features that helps you write Sass.