A cache is a system of saved files both on the client & server side that are meant to save larger files & resources that are always required for a page to load in order to reduce the overall load speed.
One of the most common web page load speed issues is that sites do not always use their cache policy as much as possible, adding more lag to load times.
The Importance Of Cache Policy & Website Optimization
When a webpage loads, a number of files are transferred between the client & the server.
Some of these files are static, meaning that they will be needed each time the page is accessed & will not change.
By having an effective cache policy, these resources will be stored by a user’s browser temporarily, so that the next time they access the URL there will be less requests in the page load sequence.
This greatly reduces the time it takes to load a page, especially when the resources are template files which are accessed across more than one page.