I used to have this setting on for quite some time. I had it set to restart every day around 2 AM and when I woke up in the mornings, I would notice that the battery seemed to drain significantly more than if it was just left alone (and by significantly I only mean about 5 percent more or so). So let's say I would charge my phone at night and right before going to sleep I would unplug it. When I woke up, the phone may have been at 92 percent with auto restart (after 8 hours standby) as opposed to just leaving it alone where it may have been at 97 percent. This was months ago so I am not using exact numbers. It was just something i noticed and not sure if anyone else noticed. Now I just restart the phone every so often right when I am about to charge it.