Downloading iOS8 means sacrificing a large amount of data from your iPhone or iPad. Its huge size i.e. about 1.2 GB (according to iTunes) needs quiet an amount of space. One thing which is more painful is that, the downloading process requires up to 5.7 GB of free space and that means deleting or transferring a big amount of data to another device.
Clearing space in your phone is a cumbersome and confusing process as decisions has to be taken about what to delete and what to keep in the phone, because most of the things seems important. Though the required space to download iOS8 can vary from user to user, as it depends upon the last updation of the software and the device you are using. So, if you have already made up your mind to download and started deleting the data, then take a look on a simple solution of this problem.
And what is that?
Sync your Phone with your computer
Sync your device i.e iPad or iPhone to your PC or Laptop and start downloading iOS8 straight from there only. After completion of the download process you can transfer the new iOS8 to your device manually. It will not take much space on the device. Also it is always preferable to update through your Mac or PC as it is more reliable than doing it OTA i.e. Over the Air which means directly to your device.
Simple way to do it!
If you are implementing this procedure then keep in mind to select the “check for update” option rather than “restore iPhone”. The “restore iPhone” option will erase all the data from your iPhone or iPad.
Use iCloud to back up your data
It is always recommended to use iCloud to back up the data on the device. To perform this process you first need to log into the iCloud through the web browser. Then you will be prompt to verify and authenticate “the digital equivalent of double-locking your doors at night” or to sign out. If you’re a user of iOS 5 or above then the data gets automatically saved in iCloud but for that you must enable the option of “Backup &Storage” from Settings and then iCloud.