One thing we notice as they come back is that they are not turned off. Instead they are just asleep. We demonstrate how to use the Kindle to each new user, and in the process, we highlight turning it off, but if the returns are an indication, many people don't get it. This has been verified to me by some Kindle owners who have come to me for troubleshooting. Their Kindles are losing their charges too soon. I show them how to turn it off properly and their problems usually end.
To turn off a Kindle, slide the on/off button that is located on the top edge of the Kindle to the right and hold it there until the screen goes gray. That sounds easy, but many people just slide and let go. The Kindle then shows a picture of famous author and may go blank after that. The Kindle is in this case only sleeping and slowing draining its battery. Also, if you slide the button to the right and hold a second too long, it comes back on again.
If you practice, you learn to turn off Kindles flawlessly. But it should not a trick to turn off a Kindle. I urge Amazon to redesign.