How much should one give to charity?

I noticed something interesting while interviewing people for an earlier column, "Huge debts, paid off fast." Several people who had retired big debts did so while also giving -- big time -- to charity.

For
example, Joy Thompson of Pullman, Wash., paid off $8,000 in debt in
eight months while giving $300 a month, more than 11% of her income, to
her church.

Adam Carroll, who with his wife retired nearly
$44,000 in credit card, auto and student-loan debt in five years, also
makes giving a priority.

"We started out with a number that was
comfortable to both my wife and I (which was 5% of net income) and
slowly worked it up to 10% of net," said Carroll, a Clive, Iowa,
resident who runs a company that provides financial literacy programs
to youth. "My goal at some point is to live on 50% and be able to gift
the rest."

When it comes to charitable giving, superdonors like investor