Is there a way to find out just how much storage you've used / have left on a Paperwhite? IE---just how many titles can I put on it?
There should be an option somewhere in Settings called Device Info (or something similar, sorry I have an old Paperwhite) that will tell you.
You can potentially have over a thousand books on it, but if you have more than a few hundred (say 400) downloaded, it will slow down your device considerably.
Home page and then Menu - Settings - Device Options - Device Info
Older Paperwhites have Menu - Settings - Menu (again) then Device Info
ah OK. I have 2,932 MB free!