Mortgage rates just keep falling. Thirty-year fixed-rate mortgages averaged 5.61 percent this week, down from 5.67 percent the week before, another record low in a string of record lows for the 30-plus years Freddie Mac has been tracking the rates, the secondary mortgage company reported yesterday.

And as rates keep dropping -- lower now than they have been since at least the early 1960s -- Americans keep refinancing their home loans, in some cases, only months after their last refinancing.

"With the interest rate drops of the past three or four weeks, it's back on the refi merry-go-round again," said Keith Gumbinger, vice president of HSH Associates, a financial surveyor and publisher.

The possibility of war with Iraq and the continued sluggish economy have been pushing investors to U.S. Treasury securities, which has brought down yields. And when bond yields drop, mortgage rates go down, too. Mortgage-backed securities compete with Treasury bonds for investors. But the various markets fluctuate -- for instance, the stock market rebounded yesterday, which sent bond yields and rates bouncing back up for the day.

"Investors are being driven out of the stock market into bonds, and that's being played out in interest rates," said Amy Crews Cutts, deputy chief economist at Freddie Mac. In the secondary mortgage market giant's survey, 15-year rates were at 4.93 percent, also a record low.

"The war is hanging over everything," said Doug Duncan, chief economist at the Mortgage Bankers Association. "And bad employment numbers last week pushed rates down as well."

Mortgage applications were at a record high in the week ending March 7, according to the bankers group. And of those applications, nearly 80 percent were for refinancings, up from 74 percent the week before.

Cutts says homeowners who refinanced as little as five months ago are applying for new loans to save money.

"Just because you refinanced a year ago doesn't mean you're not in a position to refinance again," she said. "Many people are finding that is an option."

Brian McCarthy is one of them.

McCarthy refinanced his Takoma Park house last April, lowering his rate 1.5 percentage points, to 6.25 percent, for a 15-year loan. But now, his mortgage broker is quoting him 4.875 percent for a 15-year loan, paying no points.

"I'd be a fool not to refinance again," said McCarthy. "I can lower my payment and take some cash out to do some work around the house. It's definitely worth it."

Steve Calem, a mortgage broker in Bethesda, said homeowners carrying large mortgages -- $300,000 or above -- should consider refinancing again.

"With a big mortgage, when there's even a slight move in the rate, it can be worth it," he said, because the amount saved each month is sizable enough to quickly offset the refinancing cost.

Gumbinger of HSH Associates said that any homeowner paying an interest rate of 6.5 percent or above on a 30-year loan is a candidate for refinancing.

Refinancing costs money, but brokers say a good rule of thumb is to compare how long it will take to recoup the money and how long you plan to be in the house. Homeowners can also choose a no-cost refinancing, but usually end up paying about a quarter of a percentage point more in interest for it.

Rates are low only because the rest of the economy is suffering. So will they keep dropping?

Rates may fall another week, economists say, but are unlikely to drop much more, unless there's an unforeseen negative event. They're also unlikely to go up much, they add.

"If more bad things happen, rates could be driven down even further," said Duncan. "If another significant economic indicator was negative, or if there was a biological attack with large casualties. But they can't go down forever."

Some experts predict that rates with rise when the Iraq conflict either turns into a war or is resolved peacefully.

"The prospects for a sharp spike in interest rates are far greater than a continued economic downward spiral at the moment," said Gumbinger. "As soon as there's even a minor improvement in the stock market, there will be a pick-up in rates. There was an improvement in the stock market today, so rates kicked up an eighth of a percent already."