1) It gets you in the mailbox before the competition, and,
2) It allows you to build a frequency component into your strategy. If you’re in the mail in early September, you’ve still got plenty of time to re-mail your multi-buyers in October, then put a third mailing out to the entire audience again in mid-November. That’s three touch points to your acquisition audiece during the most critical fundraising period of the year. And that’s a lot better than just a single attempt.