Sass supports both invisible and visible comments. Using
// before any Sass, this will place a comment in your code, but will not be output in the processed CSS. Using the standard
/* */ CSS comments in your Sass, when processed this will be output in your CSS.
Leaving comments or instructions in your code is just good practice. I find it essential to leave good instructions behind about my code using the invisible technique as I begin to engineer increasingly more complicated Sass.
The following example is a sample of code from the Compass library illustrating a good use of comments.
// override to change the default $default-background-size: 100% auto !default; // Set the size of background images using px, // width and height, or percentages. // Currently supported in: Opera, Gecko, Webkit. // // * percentages are relative to the background-origin // (default = padding-box) // * mixin defaults to: `$default-background-size` @mixin background-size( $size-1: $default-background-size, $size-2: false, $size-3: false, $size-4: false, ...