Blackberrys only drain their batteries if they have applications running in the background ...
It took me a while to figure this out, but I now get up to 4 days normal use from one charge on my Curve 8520 .. but I am vigilant about checking for running background apps.
From the main icons, click the BB button and select
Switch Applications to see what is running in the background ...
All that should be running other than any app you are currently using, is HOME, PHONE, MESSAGES, BROWSER, (
SMART WIFI - worth getting for conserving battery power by up to 70%), and BBM. Any other apps that are listed here, should be closed.
(Since changing my router's name to "surete du quebec" (Quebec Provincial Police) several months ago, not one person has tried to brute force attack it looking for a free wifi connection ... LOL!!)