Welcome to the forums.
You do not have to put your BB in standby mode over night. I only put it in standby mode if I don't have my case and need to place it in my pocket to prevent it from 'pocket dialing.' I very rarely don't have my case. Plus I have it password protected, so if it would pocket dial, it would be an emergency call. I would like to prevent this, so that's where standby mode comes in handy.
I also charge my device every night. Read this for more info: Maximum Battery Life - BlackBerryFAQ