Running out of storage space is a perennial problem for anybody who uses any mobile devices, including iPhones and iPads, especially if they are older models. If you have deleted all the photos, videos, movies and songs that you are willing to and you still need more space, some of the iOS native apps take up a surprising amount of space:
Apple's stock Podcasts app is a great way to follow and support your favorite podcasters, but it can also be a drain on your storage. Subscribing to a podcast through Apple's app automatically downloads new episodes to your device. While this is a great feature to keep you updated with all the latest episodes, it is also a strain on your device's storage capacity. You can navigate to Settings > General > iPhone Storage to see just how much space your Podcasts app occupies on your device.
Apps tend to pile up on the iPhone, iPad and iPod touch. Some apps are even downloaded and never used at all. Clearing out those apps that are not frequently used can simplify your iOS device and free up extra storage space. Apple makes it easy to see the last time an app was launched, which can help get rid of clutter.
Everything you send or receive through your Messages app is stored on your iPhone. This includes photos, videos, .gifs, and images. Combine this with the photos in your Photos app, and apps you have downloaded, and you can easily eat up storage on your device.
iOS 11 adds several features aimed at optimizing storage space on the iPhone and iPad, such as Messages on iCloud and the ability to offload apps.