BEND, Ore. (CNN/Money) - If you're just now shopping for a mortgage, the bad news is that you've missed out on the lowest mortgage rates in four decades.

The 30-year fixed loan rose to 6.34 percent in the week ended Aug. 29, according to HSH Associates, up from its low of 5.37 percent in June.

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But there's a bright side -- lenders have to work harder for your business these days.

Back when rates were at their lowest levels, mortgage bankers were flooded with applications, so much so that there was little wiggle room for borrowers to negotiate on rates, fees or closing dates.

"Some companies were just assigning people a closing date," said Douglas Duncan, chief economist for the Mortgage Bankers Association of America (MBAA). The time it took to close on a loan went from 30 to 50 days to more than 60 days.

But all of that has changed in just a matter of months. "Lenders don't have people beating down their door for their loan," said Keith Gumbinger, a vice president of HSH. "You're more in the captain seat than you were even a week ago."

Refinancing demand has fallen for nine consecutive weeks now and is at its lowest level since June 2002, according to the MBBA. Demand for new mortgages remains strong, though many concede that this is only because buyers are rushing to lock in rates before they go any higher.

"Anecdotally we're hearing that lenders' pipelines (pending mortgages) are down 50 percent from their peaks," Duncan said. "There is no question companies are seeing the pressures of competition."

So if you're looking for a mortgage, by all means ask: "Is that your best offer?"

As always, your first priority should be finding the lowest interest rate. And while rates have been going up, competition is expected to help hold them down, said A.W. Pickel III, president of the National Association of Mortgage Brokers.

You may be able to get the best deal on rates and closing cots from your current lender. "But don't just call your lender out of the blue," said Anthony Hsieh, CEO and founder of HomeLoanCenter.com. "See what others are offering and then go to your own lender. They'll dig into their discounts if they feel they are going to lose you as a customer."

When shopping around, be sure to pay close attention to the many variables that go into a home loan. That includes the interest rate, the terms of the loan, up-front points and, finally, closing costs.

"I would question any fee," Duncan said, adding that lenders have wiggle room when it comes to the fees they charge, including application fees, underwriting fees and document preparation fees. "Let them know you're comparison shopping among several lenders."

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Typically lenders do not have to give you a "good faith estimate" of closing costs until you actually apply for a loan, in which case they have three days to give you that estimate. But now that lenders are more eager for your business, you may be able to get such an estimate even before you apply.

Keep in mind that your good faith estimate is only any estimate. Lenders can -- and have -- surprised borrowers with new or higher fees just as they're about to close on their loan. (See "Take a bite our of closing costs.")

Of course, now that banks are tripping over themselves for your business you probably can rest easy that the only last-minute changes will be in your favor.