One of the largest culprits when it comes to chewing through the storage on your iPhone or iPad is the Messages app. From regular text messages to iMessages to photos, videos, and audio notes, they all take up space. In some cases, several gigabytes. However, iOS 8 brings with it an awesome feature that lets you set messages to delete automatically after a set amount of time. That means more storage space freed up regularly without you actually having to think about it!
Full story from the iMore Blog...