How to check is my Samsung Galaxy S4 is backed up?

As Posted Use Samsung Kies. If unsure about backup status, do another backup. A full backup of my S4 takes about 60 min. When restoring you will have to reset ringtones and alarm tones from there default and reinstall purchased apps from the playstore manually. All other settings and apps are restored. (App data is not restored} 

Hey 12blue, 

Thanks for your inquiry. We are happy to help. Have you backed up your device recently to KIES or synced to google? 

Zoe, 

Samsung Support