The Psychology Behind Asking Users For Their Email Address.
These “three laws” represent the principle of repetition. Repetition is the path to learning. And if you doubt my claims, then you can spend your time (as I did) reviewing the medical, psychological, and educational scholarly peer-reviewed research on the subject. (Relevant links are included in the sentence, “Repetition is the path to learning.”)
The more frequently you ask and/or remind the user of your request, the more likely he is to give in to your request.