Expires headers

Let's say you have a website and it loads 50 resources. How terrible would it be if, every time a user returns to the website, all 50 resources had to redownload every time. That's not ideal. Fortunately, we have the ability to cache resources.

For static content, such as JavaScript files, favicons, and other content that will not change very often, it's safe to set a long expiry. This way, when the website is accessed, these items will be in cache, and this will automatically make the website faster for your users.