Donors cite the top reason for ceasing their support is the way they are treated, from not being thanked to an avalanche of needy appeals. It is indeed cheaper to keep a customer/donor than to find a new one. Experts encourage non-profits and churches to thank donors three times as often as they appeal for donations. Remember to make thank-you messages personal, and show your recipients their impact.
My last church was the first (and only) church I had ever served where I was absolutely forbidden to see the list of donors. (Neither was anyone on the elder board allowed access to that information.) The ability to express personal thanks is only one reason why such a practice is cutting off your nose to spite your face. People didn’t know we didn’t know, but wondered why we never expressed appreciation for their faithfulness in good and hard times. We weren’t allowed to know. How discouraging.