Googles backup isn't very good. It restores some settings and your apps but not the app settings in general so I tend to not bother and if I reset I just start again from scratch.
I've been using HTC backup in the hope it might do more than what google manage but haven't actually tried it out yet.
Its a shame as full system backup is one of the few areas in which android is behind iOS IMO. I think they've improved it on lollipop but still don't think it backs up everything
Posted via the Android Central App