While Apple's iPhone dutifully caches all the data you entrust to it, some pieces of data too valuable to risk losing. Sometimes, app updates may remove things that are important to you. Other times, a crash may take it all away. If you're concerned that your iPhone hasn't been backed up recently, you can use iTunes or the phone itself to check. Find peace of mind in your data's safety by determining when your iPhone was last backed up to your computer or iCloud.
Launch the iTunes app on your computer. Your iPhone doesn't have to be plugged in to your computer to determine when the device was last backed up.
Click on the iTunes menu bar and then select the "Preferences" option from its menu.
Click on the Preferences menu's "Devices" tab to view a list of all stored backups on your computer. Each device's last sync date and time is listed adjacent to each entry in the "Device Backups" window. Hover your mouse over each listed device to determine its phone and serial number.
Tap on the "Settings" icon on your iPhone's home screen.
Select the "iCloud" option from the Settings menu.
Tap on the "Storage & Backup" option in the iCloud menu. The time and date of your most recent backup will be displayed beneath the "Backup" button at the bottom of the Storage and Backup menu.
Information in this article applies to the iPhone 5 running iOS 6 and iTunes 11. It may vary slightly or significantly with other versions or products.