What's the most underrated web development practice that actually improves site performance?

[devsing]

What's the most underrated web development practice that actually improves site performance?

 

[arindamb]

Not lazy loading the image at the top of the page. People add lazy loading to every image in the template, the hero drops into the same queue as everything below the fold, and LCP gets worse on exactly the page they were trying to speed up. Lazy loading is right for what is off screen and wrong for the largest visible element.

Close second is putting width and height on every image so the browser reserves the space before the file lands. It costs nothing and removes most of the layout shift, and it gets skipped constantly because on a fast connection nothing looks broken without it.

 

[mrlong]

One underrated practice for me is reducing unnecessary JavaScript. It’s easy to focus on image compression or caching while overlooking how much work the browser has to do parsing, executing, and managing scripts. Removing unused libraries, third-party scripts, and unnecessary client-side logic can improve load time and responsiveness significantly. It also makes the site easier to maintain.