To check to see if any of your books are still being indexed (drains the battery a little more than normally)...
From the home screen, go to Search and type a nonsense term (for example, xx or yy). If the system is done indexing books, it will display ‘No Items’. If there are still items being indexed, the Kindle will display “Indexing Still in Progress”.
Indexing happens when you add any new books. It takes a little while, but you will appreciate it when you need to find something in any one of possibly hundreds of books already on your Kindle.
If you have downloaded a lot of books, from Amazon, as well as other places, you might want to let your Kindle do its indexing at night so it will be out of the way and nice and frisky by morning.
Before going to bed at night, plug your Kindle in, leave it on, and leave it in that state for the rest of the night. Make sure WhisperNet is on in case you have any books to be downloaded or software updates to be made, giving your Kindle the ability to catch up. You will be glad you did.