Is it necessary to learn LESS or SASS ?

Question

What are the benefits of learning this ? If we already are familiar with css .

Answer 1

It's not "necessary", but 90% of the time, it's worth it.
*One of the benefits of learning a css preprocessor is that you can use variables, in other words, you won't have to keep track of a specific color's RGB value.

*Another benefit is modularity.
You can split your css into multiple files and then compile them into a single file,
OR
You can compile them separately and just import what you need.

SCSS
=====
$my_color: #9a2d68;

.header{
color: $my_color;
}

You can
"Define Once, Use Anywhere"