Many Internet browsers and also other software (especially mobile phone applications) store some offline data in their app cache. Conventional wisdom says that clearing the cache does speed up the software. But the contrary is the case. In rather rare occasions of bad web programming, the cache might store outdated content. But that's something the webmaster needs to [fix by making cache exceptions for frequently updating page elements.](https://www.lifewire.com/force-page-load-from-server-3466696) But the cache is there for a reason. The purpose of it is storing data offline for immediate access instead of needing to repeatedly download it from a web server. This does not just add speed, but spares some battery power, data volume from the mobile data plan (although the data-per-price ratio of data plans has skyrocketed during the last 5 years) and also time in case of slow Internet (e.g. if only 2G is available due to distance from 4G antennas). Also, file fragmentation is pretty much irrelevant for flash storage due to near-zero non-sequential reading latency. ([Tested with SSD.](https://www.anandtech.com/show/7173/samsung-ssd-840-evo-review-120gb-250gb-500gb-750gb-1tb-models-tested/8)) What could actually cause page errors are **cookies**. They play an undeniably important role, but I have noticed that some websites (e.g. the Wayback Machine) accumulate browser cookies over time, until the cookies get large enough for the web.archive.org server to return a HTTP 400 error. That can be fixed by clearing the cookies and maybe even blocking cookies for that site. But clearing the cache is mostly conuter-productive.