How can users manage storage on their iOS devices?

Managing storage on iOS devices primarily revolves around identifying and removing unwanted files and applications. Clearing cache and deleting unused apps directly impacts the available storage space, helping users optimize their device's performance.

iOS has built-in features allowing users to see which apps are taking up the most space, making it easier to decide which apps to delete. Additionally, clearing the cache of apps may free up some space as well, especially for applications that store temporary data. This option reflects a practical approach to maintain and manage storage without needing hardware changes or device upgrades.

The other options do not effectively contribute to storage management in a direct manner. While running a diagnostic test can provide insights into the device’s performance and health, it doesn’t facilitate actual storage management. Upgrading the device increases storage, but doesn’t solve issues with current storage on an existing device. Installing additional storage hardware is not an option for iOS devices, as they do not support external storage upgrades. Thus, focusing on clearing cache and deleting unused apps is the most relevant and practical method for users to manage their storage effectively.