One of the main reasons to use past perfect is another action in the simple past that precedes it: 

"Perhaps you didn't notice?" [simple past]   

 Bond: No, can't say I **had**. [had noticed]. I can't say I **had noticed** before you mentioned it (implied).

Other examples:

I *had noticed* that she *cleaned up* the room.
I *had seen* the movie before he *mentioned* it.