Over time, Firefox cache files can accumulate and take up a lot of your disk space. Clearing the cache will thus help you free up space on your Mac. Another reason to clear the Firefox cache is to prevent errors on the websites you visit. If a webpage was updated, you can see the wrong old information on the page because of old caches. Sometimes, you can even face issues when a page is not loading. Clearing cache will help to fix page loading issues. Also, clearing the cache will make your browser work again smoothly.