Many charities see efforts to woo small-time donors as a waste of time and money.

After all, it costs a lot to mail fund-raising letters to people who, at most, will probably donate $25 per year.

But Roger Craver and Tom Belford at The Agitator say that people who make small annual gifts are also the most likely to provide big bequests to charities they trust.

To prove their point, the fund-raising experts point to a recent essay by the direct-mail consultant Mal Warwick, who tells the story of a donor who gives $5 to a charity as a result of a direct-mail pitch. The donor then makes 22 more annual gifts at $25 — bringing the total to $425.

That same donor the made a bequest to the charity of $90,000. That initial $5 gift has now turned into $90,425.

“Yes, your small-gift fund-raising program — probably a combination of negative income prospecting and positive income donor upgrading and cultivation — must meet a ‘here and now’ positive return on investment,” Mr. Belford and Mr. Craver write. “But don’t overlook the downstream value of small-gift donors in terms of ultimate major contributions, including bequests.”

Does your organization have similar stories of people who give small sums during their lifetimes — and then left major bequests? Or are such stories the exception rather than the rule? Click on the comments link below this post to share your thoughts.