If you are able to keep your donors longer, you will raise more funds for your cause. Simple as that.
The simplest way I can explain it:
We invest in our staff and our fundraising programs. This should result in the best possible experience for both potential and existing donors. This influences satisfaction, commitment and trust, which constitute the donor’s attitude towards the charity. In other words: increased donor loyalty. This leads to the desired behaviour: higher retention rates. In turn this results in more income, which can be invested again. In projects for our beneficiaries, in staff and our fundraising program. And repeat.