Many/most organizations keep going back to the same lists for acquisition over and again. They’re good lists. They keep performing well. But you can speculate that thousands of people have become numb to your control acquisition mail package. At least to some degree, they recognize it when it arrives and say “no thanks … already decided on this one.”
Remailed often, they have become are “resisters” to your acquisition control.
One solution proven by multi-million-donor programs: Develop a “resistor acquisition package” — something really cheap in relatively small quantities and test into your most-used lists.
You don’t need to get as good a response as the control. (You don’t need to beat the control in response.) You just want to find out if there is a package that so cheap that it about the same cost of acquisition as the control.
With this, the overall prospect list can become more productive over time. In big programs, this pays off nicely with a tiny incremental increase in value. With small programs, you might have a cost-effective way to squeeze a few dozen new donors out of your best rental list.