The iPhone's lack of expandable storage space means that your internal memory is at a premium. If you have an iPhone with a lower storage capacity, you may find that apps eat up more than their share of space. When you delete an app from your iPhone, all the relevant data files for that app are also erased, such as personal settings and scores.

Deleting Apps and Data

Most apps remove all the data associated with the app when the app itself is deleted. This cleans up space on the phone, especially in those apps that store a lot of extra data, such as social media applications and alternative camera applications that maintain extra copies of your photos. If you find that an app takes up too much space on your phone, you can reduce it by deleting and re-installing the app.

iCloud and App Data

In addition to the app data saved on your iPhone, you can also choose to have app data backed up to iCloud. As such, even if you've deleted the app from your iPhone, the data may still be accessible in your iCloud account. If you deleted an app but still need the data, you can back up from this saved information. If you're worried about sensitive data information getting into the wrong hands, you can choose to delete this information from your account.

Tools to Clear Cache Data

If you want to erase unnecessary app data without deleting and reinstalling the application, consider using a third-party management tool to access data on the iPhone and delete cache files. While removing cache files will not damage the app or iPhone, accessing the file system can be risky if you delete the wrong file. Also, some apps may take longer to load when the cache has been erased. Applications like iFunBox, iTools, and iExplorer all allow you to access your phone's folder structure and manage data.

Erasing All Data

If you're passing on an old iPhone and worry about the new owner accessing your old data, the best course of action is to do a factory reset. This removes all apps, customized settings and account information entered into the iPhone. Open the "Settings" apps, go to "General," and select "Reset" to begin the process of erasing your iPhone. Choose "Erase all Content and Settings." This process may take a few hours if you have an iPhone with a lot of storage.