Q. We’re considering a capital campaign. I understand most campaigns collect the money over three years, but what is the rationale for that length? Why not five, for instance? And how should we involve the people who join the congregation toward the end of the campaign or afterward? Should they be asked for contributions as well?

A. Wayne Clark, the Unitarian Universalist Association’s director of congregational fundraising services, says three-year campaigns offer many advantages. Longer campaigns tend to have greater slippage in the rate of pledge completion. In a three-year campaign, he said, a 95-percent completion rate can be expected. In a five-year campaign, it often drops to 90 percent.

Clark said that a five-year campaign might be warranted if a financial feasibility study predicts no significantly large gifts, meaning all the gifts are likely to be given from members’ salaries.

Clark encourages congregations to ask new members to make a financial commitment to the annual operating budget and capital campaign when they join.

How often can a capital campaign be conducted? “Depending on how much energy there is, and the scope of the remaining capital project, a very few churches can run back-to-back campaigns,” says Clark. In general, he says, capital campaigns should be separated by at least five to seven years.