My Droid Turbo 2 keeps beeping a notification sound but does not indicate the reason. I suspect the 50 or so beeps I get are telling me I have received e-mail. How can I turn that off, but keep the other notifications active? Is there a way to apply individual sounds for different types of notice as one can do with special ring tones for certain callers? How do I empty my cache to avoid battery drain? Is this accomplished by clicking on the small square at the rt bottom and individually closing each recently used app or is there a shorter way or a way to have the cache cleared automatically each time an app is closed?