(MONEY Magazine) – For many people, the question is not whether to give to charities, but how much. Although the answer is personal, of course, a few guidelines may help. Some churches, notably the Mormons and fundamentalist Baptists, stick with the Old Testament standard for giving -- 10% of goods and property. Many other churches and charities, however, suggest cutting the traditional tithe in half -- and then supplementing it with volunteer service. The Independent Sector, a Washington, D.C. coalition of 650 nonprofit and corporate groups, urges a strategy called ''fiving'' -- donating 5% of your income and five hours a week of your time. Most Americans, however, don't measure up to such standards. Over the past two decades, they have contributed 1.9% of personal income on average. More remarkably, the poor give the most -- last year, households with incomes of less than $10,000 donated 2.8% of their earnings to charity, vs. 1.7% from households earning $75,000 to $100,000. ''Those who are poor see great need around them and share what they have,'' says Brian O'Connell, president of the Independent Sector. Anecdotal evidence suggests that baby boomers are beginning to open their checkbooks more freely. ''Virtually all of my 175 clients give something,'' says Joan Gruber, 40, a certified financial planner in Washington, D.C. ''And a lot of them work in places like soup kitchens as well.'' -- M.T.S.