(MONEY Magazine) – Confused and confounded by today's fast-changing travel packages and prices? Here's a solution: team up with a dedicated travel agent who can save you hundreds of dollars -- and steer you around travel nightmares. Most travelers have gotten part of the message: they use agents. Currently, more than 80% of all airline tickets are booked by agencies, up from 38% in 1978. In addition, fully 90% of all packaged tours and 95% of cruises are booked by agents, according to the American Society of Travel Agents in Alexandria, Va. Consumers still tend to think, however, that all travel agents are created equal. They're not. Different agents' suggestions for the same trip range widely in price, perks and comfort (for examples, see our quiz, ''How You Can Test-Fly a Travel Agent,'' on page 112). Another indication: when the New York City Department of Consumer Affairs called 49 travel agents last year requesting the lowest round-trip fares for flights from New York to several other U.S. cities, the rates varied by as much as 115%. ''The main reason for the fare differential is simple,'' says the report. ''Some travel agents are lazy, negligent or poorly trained.'' So the key to special deals and memorable vacations is learning how to separate good agents from bad ones. The following guide to choosing a travel agent was compiled from dozens of interviews with industry insiders and critics. Here's what you need to know: -- Is the agent reputable? The country's roughly 40,000 travel services, up from 27,000 in 1985, now run the gamut from computerized mom-and-pop shops to local branches of high-volume chains; from bargain wholesalers to velvet-glove packagers; and from airline tour desks to ''niche'' agencies that specialize in one activity or destination, such as cruises or Africa. The problem is that virtually anyone can call himself a travel professional. Only nine states require any type of agent regulation or certification: California, Florida, Hawaii, Illinois, Iowa, Ohio, Oregon, Rhode Island and Washington. Faced with the clutter of choices, remember that it's the experienced and knowledgeable individual agent who counts -- not just the agency. One credential worth noting: the certified travel counselor (C.T.C.) designation. To get it, the person has to have been in the business for at least five years and to have completed travel courses. Of the more than 200,000 travel agents in the U.S., only 14,000 have earned C.T.C. degrees. For names in your area, call the Institute of Certified Travel Agents (800-542-4282 or 617-237-0280). Other industry affiliations, such as an agency's membership in the American Society of Travel Agents (ASTA), should not be your only measure because the qualifications are hardly rigorous. At the very least, seek out an agency that has been around for five years or more. Also, check with your local Better Business Bureau to learn whether any complaints have been registered against the company. -- Is the agent working for you? On average, a travel agent earns only $16,000 annually. ''You have to remember,'' says Chicago travel industry attorney Beverly Susler Parkhurst, ''this is one of the few businesses that have never charged for professional advice, though some are starting to institute service fees.'' Most agencies collect commissions on sales, typically 7% to 15% of an airline ticket, hotel rate or tour package price. On top of that, suppliers often pay as much as 30% more, known as ''commission overrides,'' to high- volume producers. To pump up the volume and make more money -- particularly in these tough times -- agencies tend to channel their business to as few suppliers as practical. In other words, they may put their own financial interests ahead of your needs. A recent poll in Travel Weekly, a leading trade publication, revealed that more than a third of travel agents admit that commission level is a major reason they recommend one tour to clients over another. Most travel pros will not answer questions about commission overrides. To check whether an agent is biased toward a supplier, ask why he or she recommended a specific tour operator or airline, and judge whether the answer makes sense. Then shop around at other agencies to compare prices and choices. Once you come to trust an agent, you can skip the homework. -- What type of computer reservation system (CRS) does the agent use? In the late 1970s, airlines introduced computerized pricing systems, called yield management, which have revolutionized airline reservations and sales. These proprietary programs allow carriers to match unsold seats to demand, hour by hour. When a fare war is raging, airlines may make as many as 200,000 fare changes in a single day. Travel agents use four major computer reservation systems: American Airlines-owned Sabre system; United's Apollo; Continental's System One; and Worldspan, owned jointly by Delta, TWA and Northwest. As a result, your best fare on major airlines will come from a diligent agent, not from calling airlines directly. But be alert for agents who always punch up the same airline. The U.S. Department of Transportation is currently reworking the rules to prevent the CRS from favoring an owner-airline. What's more, the states are on the case. Attorneys general in 27 states announced that they are monitoring the development of a new version of Worldspan, due on-line in 1993, to make sure the system is not biased toward its three owner-airlines. Also, some no-frills airlines, like Southwest, do not list fares on any CRS. To consider those fares, ask your agent to call the airlines directly. -- Will the agent take the time for a creative computer search? To find the lowest fare, an agent must log a lot of time on the CRS. Make sure he or she uses direct access, which taps into the airline's main computer system to get the most-up-to-the-minute information. A hard-working agent will also explain that you can nab a better deal by shifting your departure by a day or a few hours, or by flying into a different airport. For example, it recently cost $420 to fly round trip from New York's La Guardia to Los Angeles' LAX airport. If you booked from JFK to Orange County airport (a 45-minute drive from L.A.), however, the price dropped to $298. Most agents will also negotiate with consolidators -- the wholesale brokers that purchase discounted airline tickets in bulk. Business fliers and last-minute travelers can benefit from an agent who specializes in ''back to back'' or ''hidden city'' fares, in which you get off the plane at the connecting city rather than at the last leg of a flight. Hidden-city deals are not illegal per se, but airlines say that those tricks break their rules. As a result, airlines have begun to monitor some routes -- such as New York to San Antonio via Dallas -- to discourage such ploys. If caught, you'll end up paying full fare. On back-to-back tickets, which don't break any rules, you save money by purchasing two round-trip tickets, which include a Saturday night stay, rather than one round-trip, full-fare coach ticket at midweek peak prices. -- If the fare drops after you purchase your ticket, will the agent reissue a nonrefundable ticket for the better price? In most cases, agents can reissue such a ticket if, say, a fare war breaks out. They may resist, though, because they must then refund part of their commission to the airline. -- Does the agent have an automatic fare-checker program? Designed to beat the yield management system, these are new computer programs that can constantly search for the lowest price. Last May, for instance, ) American Airlines tried to put a damper on this technology by charging travel agents for extensive searches, but computer whizzes simply sidestepped the problem by reducing the number of computer checks. You probably get the best fare by buying a ticket at least two weeks in advance. But if you need a last-minute flight, a fare-checker system can be a real boon. Most agencies reserve the technology for corporate clients, but two agencies that offer the service to all travelers are Associated Travel Management in Santa Ana, Calif. (714-754-0280) and Sunbelt Motivation & Travel in Irving, Texas (214-717-2988). -- What happens if the agency goes bust or if the airline or tour operator goes belly up? Only seven states require travel agencies to provide any kind of consumer protection against their going out of business, such as a bond or an escrow account: California, Hawaii, Illinois, Iowa, Oregon, Rhode Island and Washington. This protection is very limited, however. For instance, when Apollo Travel in San Pedro, Calif. went bankrupt last July, among its creditors were an estimated 300 clients claiming losses of approximately $900,000. The same is true for suppliers. The agency is not liable if an airline or tour operator folds before you depart, as long as the agent has correctly forwarded the funds and can prove it checked out the operator somewhat. One way to protect yourself is to use a credit card to pay for travel expenses. Federal law allows you to dispute an item charged on your card for which you didn't receive the service or product. Usually you must submit a written claim to the issuing bank within 60 days of receiving your statement, though some banks are more flexible. If you're paying in advance for a trip, try to pay only the deposit, then deliver full payment 45 days before your scheduled departure. Most of the time, a savvy agent will be your best source for travel deals. It may take some work to find one, but it's an investment that can pay off for years.