The concept of DRY code is simple, Don’t Repeat Yourself. So if you look at some code you’ve just written and notice it’s looking a bit moist, AKA the same stuff repeating over and over, there’s a good chance it’s an opportunity to refactor.

This is also true with variable declaration. Take the this example:

var umbrella = "open";
var raincoat = "on";
var gumboots = "on";
var music = "Singing in the rain";
var action = "Jumping in puddles like a man";
var danceMoves = "The Swim";

Notice how when declaring loads of variables we tend to repeat var a lot? Not very DRY now is it? Let’s put a towel over it:

var umbrella = "Closed",
raincoat = "off",
gumboots = "off",
music = "Walking on sunshine",
action = "slip, slop, slap",
danceMoves = "The twist";

Small difference’s like this add up over the course of a project so it’s best to make these your default habits when you’re a beginner.