I have a Nook rather than a Kindle, so I don't know if Kindle has this feature.
Look & see if it has "airplane mode". That saves a lot of battery life, while still being able to read all you want. The only thing is, you can't do any downloading or anything other than reading unless you turn it back to regular mode.
Collections? Oh oh, I am missing something! Must try this. I need to sort our my Amish fiction from Zombie Fiction! lol!
I have collections on the Kindle app for my PC and it worked great until (all of sudden) that app is no longer compatible with my PC. Sometimes I really do like sitting at the table and reading on a larger screen. It could be the last window upgrade knocked it out, but I haven't figured out who to ask. Windows Help is no help and I don't want to pay for answer.
I'll try again to find the collection key on my Fire.
Re Kindle batteries... I have the "2.0 " version, not the Fire, and normally the battery lasts for many many hours of reading. Transoceanic flight levels of reading. When it doesn't I seem always to find that I've left the wifi connection on...that drains it much faster. I swear sometimes it seems to have turned itself on, as I have no memory of doing it, or was just sure I'd turned it off after my last book order... :)
Re the collections thing...to repeat a question raised above... I had no trouble creating a collection... but then the books were still ALSO in my list of 500 or so books, so didn't really eliminate the clutter. Am I missing a step? For example, I have several pages of "Reacher" novels, or so it seems, and put them all in a collection just fine... but they seem to still be in my "cloud" list.
I have to turn wifi off now everytime I turn on the kindle. It wouldn't just stay in airplane mode. When they updated the operating system (or whatever they call it) they switched from being able to just turn wifi on/off but having to go in and noodle with airplane mode each time and it defaults to on each time now.
I hope they get all of these gremlins resolved before I buy.