Just ran a promo. It worked out that 7 emails went out about it. (I wasn't aiming for 7, it's just a coincidence).

Just over 1/5th of the total gross of that promo came in from the first 2 emails.

Translation... had I mailed only twice, we would have made roughly 20% of the total.

AND... had I then instead mailed a different offer twice... I'd not only barely tap the potential of that offer too, but now I would have confused my audience's attention and killed the integrity of my promotions seeing as I'm back to back promoting different offers.

I'd rather promo one strong, well converting, relevant offer 10 times in a given month... vs 5 offers 2 times each or EVEN WORSE, 10 offers once each. And all things being equal, I'd wager that I'd make more endorsing that ONE offer vs. 10.

And from an affiliate/merchant relationship standpoint...

To the one select merchant that I whole-heartedly endorsed that month, I just pulled in a very worthwhile number of sales. I'm on their radar. I'm in their good books. Not because I just "mailed" but because I sent them a lot of profits. And that's worth a lot more than me mailing for 5 offers and each of those merchants seeing less than favorable results.