You've been tasked with developing a new front end feature. HTML, CSS, and JavaScript are nothing new to you, in fact you even know a few tricks to get this feature out the door. It doesn't take you long and the code works like a charm, yet you have a looming suspicion that some of the code might not be up to par. You're likely right, and you're definitely better than that.
We often write code without paying attention to the bigger picture, or overall code base. Upon stepping back we notice areas of duplicate code, ripe for refactoring. It's time to build more modular front ends, focusing on the reusability of HTML, CSS, and JavaScript, and to take maintainability to heart.