Starting to doubt whether your dealer knows what he's talking about? Or maybe you think you've got a valuable antique on your hands but you're not so sure? Here are some things to consider before turning to the professional.

1. "Be nice and I'll lower the price."
If you like to shop for antiques, then you probably also like to haggle over prices. After all, you may not even know what you're looking for when you walk into an antique shop, but you probably know one thing — that the dollar number on the price tag isn't always the amount that the dealer is actually expecting to get. For most buyers, though, the negotiation is shrouded in one mystery: Just how much wiggle room do I really have?

Lincoln Sander, an antique dealer in Redding, Conn., explains that dealers generally have what's called a "trade price," that is, a price for which they'll sell the item to another dealer, a known collector or a regular customer. The discount can be significant — often as high as 20% — and most dealers build it into their markup when pricing an item. What you may not know is that it may also be available to you as a first-time customer. The dealer may offer you the special price if he sees the potential for building a relationship with you, notes Sander. But your luck also depends on how presumptuous you are in your negotiating. "Ask in a nice way," Sander advises, "with the idea that you might or might not get the price." Pat Garthoeffner, a dealer in Lititz, Pa., agrees that manners go a long way. "Never make an offer (by saying) 'I'll give you...' or 'Can you take...?' That's just insulting," she says. The phrase that makes her most likely to give customers a break? "I think the best thing to say," says Garthoeffner, "is 'Do you have any room...?'"

2. "Need an appraisal? Don't look at me."
Congratulations, you're an antique dealer! Want to call yourself an appraiser, too? Go right ahead. In fact, of the 30,000 to 50,000 people in this country who call themselves personal-property appraisers, just 10% are professionally trained, according to Christian Coleman, executive director of the International Society of Appraisers. The reason is that appraisers are completely unregulated, with no educational or licensing requirements. "Anyone can hold himself out as an appraiser of fine arts, antiques or whatever, and can even obtain accreditation," complains Marshall Fallwell Jr., an antique appraiser in Nashville.

And those dealers who do boast of their appraisal credentials aren't necessarily well trained. ("Your pet cockatiel could be a member in some of these (appraisal) organizations," says Irene Austin-Gillis, an appraiser in Providence, R.I.) Even the four biggest and most respected groups that offer credentials to appraisers don't have the most rigorous standards for admission. In fact, just one, the American Society of Appraisers, requires all of its members to pass a test on a specific area of appraisal expertise — Oriental rugs, say — before gaining entry. The remaining three test the bulk of their members only on general appraisal standards and practices. Says Paul Dewees, president of one of them, the Certified Appraisers Guild of America, "Our test is general, primarily because the type of work our members do is usually not high-end appraisals. Our members are trained for the everyday estate sale."

But the problem isn't just that many dealers can't give you an accurate appraisal. It's also that they shouldn't. Austin-Gillis explains that you shouldn't seek an appraisal from anyone who's even affiliated with an antique store or gallery. "Only someone who's not going to buy or sell the property will give you its true value," she says. Thinking of getting your goods appraised online? While you may get the objectivity and accuracy you are looking for, be aware of the fact that this is a brave new world and standards of practice are only now being created. For example, some insurance companies will accept online appraisals, but they won't always pass muster with the IRS or a divorce lawyer.

3. "Even I've been duped by fakes..."
If you're a regular on the flea-market circuit, you know there's no shortage of reproductions out there. "If it's repro-able, they're doing it," says Pat Garthoeffner, adding that she was recently at an "antique" show where there was a rug on sale for $1,200 that she had bought at retail store T.J. Maxx for $36.

The trouble is that even some professional dealers can't tell the difference between a fake and the real thing. Donna O'Brien, a dealer in Brownsville, Tenn., admits that she was taken earlier in her career when she purchased what she thought was an authentic Qing Dynasty figurine for $100. "Since then, I've been in stores in Memphis and seen the exact same piece," she says. "And when you see six of them sitting on the shelf, that's a dead giveaway." And O'Brien is pretty sure that she's not the only one who's been had. "I'm in good company," she says. "Just about everybody has been fooled. They say even the experts at Sotheby's have been fooled."

Part of the problem is that the word "antique" covers a wide range. There's furniture, jewelry, art glass — the list goes on and on. Any buyer who expects her dealer to be knowledgeable in too many areas is dreaming. "A person who can answer a question on any object," cautions Gary Espinosa, director of appraisals for the auction house Butterfields, "is a person you should stay away from."

4. "...so you should demand a guarantee."
Given that you can't count on your dealer to be certain of what he's selling you, the last line of defense is a written guarantee — a piece of paper that you are more than entitled to. But don't expect your dealer to necessarily cough one up willingly. Sander says that your request might be met by a suspect dealer with resistance or a simple "no"; just as likely, the dealer may try to hedge his or her bets by saying, "That's what I believe the piece to be." In that case, caveat emptor.

As a buyer you should demand more, say the experts. "A dealer should be 100% willing to describe the condition in full and guarantee things," says Leigh Keno, a dealer in New York who's known for his appearances on the PBS hit "Antiques Roadshow." A true guarantee, he adds, should include a detailed description of what the item is, when it was made and what parts, if any, have been repaired or replaced. Armed with that, you can be sure that you'll always get a full refund if an item turns out to be something other than what you — and your dealer — thought it to be.

5. "My restoration work is a disaster — period."
If you're buying something used, repairs are usually a good thing. Not when it comes to antiques. Many types of repairs can seriously reduce an item's value. And you may need to look closely to discover artful touch-ups.

For Lyn Fontenot, author of "Antique Furniture: How to Tell the Real Thing From the Fake," it was early morning light that tipped her off. While delivering a lecture in Puerto Rico, she stopped in an antique shop and found what she thought was a very special piece — a 16th-century Italian wood carving. Intrigued, she asked the dealer to send the carving to her hotel room so she could examine it more closely the next day. When she did, she found that about half the carving had been replaced and that some of the wood cuts were made by a modern saw.

While the repairs may have made the piece look better, they had the opposite effect on its value. Untouched, the piece would have been worth about $7,000, notes Fontenot. With the repairs, its value dropped some 60% to 70%.

Even a simple cleaning can make a big difference. When looking at wood furniture, for instance, be sure to ask specifically if anything has been done to the surface, since a cleaning that improves a piece's finish could strip away much of its value. Keno points out that a piece of 18th-century furniture that's been overly cleaned could see its value cut from $100,000 to $20,000 as a result. 6. "This is not a good investment"
While a turbulent stock market may lead you to seek the safety of investing in a piece of well-built furniture, be forewarned: The bulk of what's for sale in the antique market is't going to appreciate at any dizzying rate. "I don't think that people should be buying antiques as investments," says Lincoln Sander flatly.

But what about those people you've heard of who have made a killing buying high-quality antiques? For the most part, those people have held on to their purchases for a very, very long time. "I think that the people who have done well from a financial point of view are those who bought (antiques) with the intention of never selling them. They bought them with the idea that they would take them to the grave," Sander adds. Well, you may not need to take your furniture that far, but don't expect to turn a quick profit either. "In the vast majority of cases," says Kyle Husfloen, editor-at-large of Antique Trader publications, "you are going to need to keep a collection together for probably at least a minimum of 10 years up to 25 years or more to see any important escalation."

Most of all, be aware that an item's value will ebb and flow with its popularity. "If you invested in Beanie Babies," Rudy Franchi, a collectibles appraiser who makes regular appearances on "Antiques Roadshow," points out, "you would be up to your ass in them now."

7. "Not happy? I'll give you your money back."
No business person wants to be sued. But for an antique dealer, the prospect is particularly unpalatable, since most are sole practitioners in a business where reputation reigns supreme. Antique dealers "live by their reputations," notes John Collins Jr., a rug dealer in Newburyport, Mass. "No one wants unhappy customers." All of this adds up to one truth: If you think you've been had by a dealer, don't throw in the towel, even if you failed to get a written guarantee.

Marshall Fallwell Jr. has been called on dozens of times to do appraisals for clients who have bought "antiques" that turned out to be fakes. And in every case, he says, those who have gone back to the questionable dealer with an appraisal in hand have gotten their money back.

Despite this success rate, Fallwell still finds that some clients who have been taken just "go off and lick their wounds." Don't be one of them. "I think they see having gotten nailed as an indictment of their own taste," he says. "Somehow if you have the taste and money to buy those things and you get a fake, that means that you really don't have that much taste. And that, of course, is absurd."

8. "I'm in cahoots with your interior decorator."
Remember that rosewood cabinet that your decorator said would look fabulous in your living room? Well, it's possible that she had another motive besides making your home look its very best.

It's common practice for an interior decorator to offer to do your antique shopping for you, either recommending that you buy a specific piece from a certain dealer or simply going out and buying it for you. And especially when the decorator and the dealer have an established relationship, the decorator, in many cases, will earn a commission for her trouble. Some in the business consider "commission" a generous description of the payment. "Do decorators get kickbacks from antique dealers? Oh my goodness, all the time!" exclaims one New England appraiser.

The trouble is that such an arrangement sets up an inherent conflict of interest, putting the decorator in a position to benefit financially from buying certain pieces from certain dealers. As a result, you should make sure that your decorator discloses any such payment arrangements — before the shopping begins.

9. "I don't sell antiques."
What's the definition of "antique"? Contrary to what most people think, the term isn't always synonymous with "old." In fact, to technically qualify as an antique, an item must be at least 100 years old. That means that the 1930s Art Deco desk that you just paid up for doesn't qualify.

Most experts agree that the term "antique" is often not held to its strictest definition. And the problem has gotten worse in the past few years, as phenomena such as "Antiques Roadshow" have brought the world of antiques into the mainstream — and into your neighbor's backyard. "Everybody and his kid brother now has a tax number and is a professional dealer in old stuff," explains Fallwell. "(What they're selling is) not really antique, because there aren't that many antiques left," he adds.

The trouble is that dealers know that most shoppers aren't aware of the distinction. And armed with that knowledge, some dealers will overuse the word "antique" in order to get buyers inside the shop. The truth is that much of what is sold today under the "antique" rubric should really be referred to as "collectibles," that is, stuff that's less than a century old whose value has been enhanced by widespread interest. There's only one problem, explains Garthoeffner: "If the sign in front of the shop said 'collectibles,' people probably wouldn't go in." You might not want to, either.

10. "Hit the highway."
As with most things, the Internet has totally changed the nature of the antique business. Whether you are looking to buy that last dish to complete your collection or unload a Queen Anne chair that you're tired of, you're no longer confined to doing business with your local dealer. The Internet not only allows a skittish buyer to educate himself without being at the mercy of the dealer, but it also links up a huge community of buyers and sellers in a quick and seamless way. Sites like AntiquesAmerica.com and Circline.com provide reams of information for buyers who just want to know a little bit more before they plunk down their credit card. Reverse auction sites such as eWanted.com are a great place to track down obscure and hard-to-find collectibles. And eBay, because of its heavy traffic, is perfect for individuals who are trying to sell items for top dollar.

David Amer, a collector of "precasino" Atlantic City memorabilia, knows just how valuable the Internet can be. After spending five or six years schlepping from shop to shop looking for a few specific items to round out his, well, somewhat obscure collection, Amer had great luck in just two weeks after posting a listing on eWanted. His greatest coup? Finding silverware from the now-defunct Ambassador Hotel, where his mother worked as a pool attendant decades ago. "There was a slim chance in hell that I would have walked into the right antique store (and found that)," notes Amer.

Additional reporting by Noah Rothbaum.