The day of iOS 8 has finally arrived but in order to install it on your iPhone, iPad or iPod Touch, you’ll need free space—up to 5.7 gigabytes depending on the phone model, according to our resident installers. If you have a 16 GB phone, this means a massive chunk of your photos, videos, music and apps.
To find out how much storage you need, go to Settings > General > Software Update. (You might be prompted to update to 7.1.2 instead of iOS 8—update that first, then it’ll prompt you for iOS 8.) Once you have the iOS 8 screen, it will say whether you can download the update or if you must clear out space first.
One place to start, if your memory is full, is trying to update your device by connecting it to a computer running iTunes. This may get you around some of the size requirements.
If you are updating directly on your device, the first trick is to delete all the apps you no longer care about, and then check to see if that’s enough. In our testing, even when it asked us to free up more than 5 GB of space, the install sometimes proceeded even if we freed up less. See if you can sneak by.
Another trick, suggested by our friend Dwight Silverman at the Houston Chronicle, is to delete lengthy, media-laden iMessage threads from within the Messages app.
Deleting Photos & Videos
If those don’t work, the quickest way to create space is to delete photos and videos.
Don’t trust iCloud to have all of your photos backed up. To safeguard your images, the simplest approach is to plug your device into your computer, copy all of the photos to a folder, then delete the copied images from your phone. On a Mac, you can use iPhoto or Apple ‘sAAPL +0.71% super-simple Image Capture app. On a PC, you can manage your photos via iTunes.
If you back up your photos to a cloud service like Flickr or OneDrive, go to your cloud account and confirm that all of your photos— videos, too—have been uploaded. There may be gaps based on your connection settings or flukes in the update process. If you can confirm that all your photos are safe, delete them from your phone.
Just removing those media files should free up enough room, but you can also knock out big apps, either from iTunes or right from your phone.
Focus on the larger apps that you don’t use that much, or the ones that can be easily replaced once the update is finished. (Remember, a good chunk of the iOS 8 installation storage requirement is temporary.) Kids games, navigation apps with onboard maps and cloud-connected services like Spotify are all good targets. Avoid deleting apps that may contain your personal data or projects.
You can spot your own best candidates by looking at Settings > General > Usage, or by selecting the App tab in iTunes and sorting by size.
Games are another big storage hog, but be careful when deleting them. If you play a game that syncs to Apple’s Game Center or Facebook FB +0.46%, your progress can be restored. But if you can help it, don’t delete any games that you haven’t logged into via a cloud service.
Once you’ve cleared out the required storage, go back to Settings > General > Software Update and click update.
… And then wait—somewhere between 30 minutes and an hour in the current rush—for the software to load.
Source From http://blogs.wsj.com