Have you ever received the warning that your iPhone, iPad or iPod is running out of free space? If yes, you'd better take immediate measures to optimize iPhone/iPad/iPod storage, or they will not be able to perform the general functions of downloading new Apps, receiving pictures, sending voice messages, etc. What's worse, you may even fail to install the latest iOS 8! So follow the 3 ways below to free up any potential storage on your iOS devices and make room for iOS 8.2/8.1/8.
Note that each photo can easily take up 2MB and video could approach hundreds of MB. With hundreds or thousands of photos, you'll quickly eat up storage space on iPhone/iPad/iPod Touch. The best solution is to use iPhone Care Pro to transfer them to your computer that iTunes cannot achieve: First connect iDevices and launch the program, next select those files you want to transfer under "File Manager" category and click "Export to" to transfer them to your specified destination folder on PC, and then delete those from iOS devices afterwards.
In addition to that, you can navigate to Settings >> Options >> Prefer standard definition videos in iTunes to set standard definition videos as a priority and deleted those videos you've finished watching timely.
Navigate to Settings >> General >> Usage and check how much space does each App take up. Then delete those which occupy great space. Take Rage HD for example, the popular game App should eat up 2GB of space. Alternatively, you can launch iPhone Care Pro and enter "File Manager" category to delete unnecessary Apps with one click.
Besides, you can absolutely delete all music and use iTunes Home Sharing to play music. Alternatively, you can use Apps like Pandora, SoundCloud, Rdio, etc. to stream music on iPad or iPhone without actually taking up precious storage space.
You can also totally rely on the all-in-one cleanup tool: iPhone Care Pro! With it, you can not only easily remove photos/videos/music, deleted occupied Apps on iPhone, iPad and iPod Touch, but also get rid of all junk files (cookies, caches, temp files, etc).
First connect iPhone, iPad or iPod touch to PC. Then click "Speedup & Clean" from the primary interface and choose either "Quick Clean" or "Deep Cean" to scan different types of junk files. Next, select file types you want to clean under each mode and click "Start Scan". After scanning, just click "Clean Now".
After all these operations, I bet your iOS devices would reclaim large storage and you can go on installing iOS 8. Congrats! Your iPhone, iPad or iPod touch can function normally again and update to iOS 8 as well. And for you own benefit, please check how to fix stuck iOS in case your iDevices get stuck during iOS 8 update.