Most first-time home-buyers get a plain vanilla mortgage - one that amortizes over 30 years with an interest rate and monthly payments that never change. If you actually stay in the house for three decades, you'll own the property free and clear.

Such a mortgage inspires a feeling of security among home-buyers, which is why it's so popular. But keep in mind when you set out to look at houses that you pay a premium for such security.Investors who buy mortgages on Wall Street demand higher interest rates for 30-year mortgages because, from their perspective, the longer term presents more risk. If they're earning 7.5 percent on your mortgage and the market rate surges to 10 percent, you're in luck - but they're stuck. The value of their investment falls.

If you're willing to take on some of the risk of rate change yourself, you can get a lower interest rate on your mortgage. Last week, for example, the Mortgage Bankers Association reported its members were charging an average of 7.03 percent for a 30-year fixed-rate mortgage, 6.66 percent on a seven-year balloon and 5.97 percent on a one-year adjustable mortgage.

As you can see, the more risk you take on, the lower rate you can get.

But statistics consistently show that most homebuyers are risk-averse. The Mortgage Bankers survey showed that only 11 percent of conventional mortgages closed the week of June 5 were one-year ARMs. And even fewer buyers - 1.1 percent - chose a balloon.

Nevertheless, you might want to do a little research before settling on a 30-year fixed-rate mortgage. Lenders now offer many products that might fit your situation better. If you plan to stay in a house 10 years or less, consider a 10-1 mortgage. It has a fixed rate for 10 years, then adjusts every year after that. You'll probably never get to the adjustable years.

Another mortgage that might work in such a situation is a 7-23. You get an initial interest rate that lasts seven years; in the eighth year, the interest rate is adjusted to whatever market rates are at the time and that's the rate you pay for the remaining 23 years of the loan. With luck, your mortgage payments could fall after seven years.

Alternately, a 7-1 mortgage has a fixed rate for seven years, then becomes adjustable. And a seven-year balloon offers fixed payments for seven years and then ends - you have to refinance, sell the house or pay cash for the remainder due.

You can get similar variations for mortgages that are fixed for initial periods of five years and three years, then turn into various kinds of ARMS or balloons.

If you find the house of your dreams and are pretty sure you won't be moving again, go for the 30-year mortgage. Otherwise, consider a shorter term. You don't need to pay for security that you won't need.

A survey by First Republic Bank found that luxury houses sold at record or near-record levels during the first quarter of this year in San Francisco, Los Angeles and San Diego. "Multiple offers over the asking price are common up to the $2 million price range," said real estate agent Leslie deBretteville in San Francisco.

Let's hope those buyers fare better than some Californians who bought just a year earlier. The Mortgage Information Corp. reports that serious mortgage delinquencies on conventional loans made in 1997 were more than double the national average by year's end in some California communities.

With 100 percent being the national average, Los Angeles delinquencies were 222 percent, Redding's were 244 percent and Riverside's 178 percent.

The worst delinquency number, though, was in Miami, with 567 percent. Other cities with way-above-average numbers of new homeowners at least 90 days late on payments or in foreclosure were Tampa-St. Pete with 200 percent; Orlando, Fla., with 256 percent; Washington, D.C., with 189 percent; Scranton, Pa., with 211 percent and New York City with 189 percent.