One reason is the identification effect . You tend to identify yourself with a particular brand or supplier when you have invested some of your money in their products or services. You like to feel that you have made an intelligent choice. There may also be a buying mode effect . Human nature is such that most people do not make discretionary purchases regularly week after week, but only in spurts, when they are in the mood.
Catalogers always pack another catalog in the bottom of the box when they fulfill orders.
If the customer likes your dress, you may get a second response because she identifies with you or because she is still in the buying mode . Recency works, and you can prove it very easily and at almost no cost at all. The most recent folks are 5, the next are 4 etc. It always happens. Once you understand this fact, you can build it into your marketing tactics.