After 15 years of traveling the country, paying all of his own expenses and looking at countless wannabe valuables for 12 hours or longer at a time, it's easy to think the routine of an Antiques Roadshow appraiser might get older than even the best of the items he looks at.

That would be an inaccurate appraisal, one realizes, after talking with Baltimore antiques expert and dealer J. Michael Flanigan, who has done nearly every Roadshow event since the PBS series started taping in 1996. Flanigan is one of about 150 professionals who make up the program's pool of appraisers -- about half of whom are asked to each event.

[The latest edition of Antiques Roadshow is televised Monday, Jan. 31, at 8 p.m. ET. Check local listings.]

In a recent telephone conversation, Flanigan gave a number of good reasons why he has remained a furniture and folk-arts appraiser on the series since its inception, and hasn't missed a city stop on the annual tour of show tapings since 2001. Near the top of his list was the fun of making his mother so happy. He had written a book and assembled some impressive shows before television, but none of these things matched her reaction to her son's presence on this popular new show.

"I do it because of the look on my mother's face," Flanigan said. "The minute Roadshow started, people started calling my mother. If I had written her a check for a million dollars, she wouldn't have smiled as much."

Beyond that personal motivation, there are a number of solid professional reasons on Flanigan's list. An important one is meeting the people who bring their items in for an expert opinion. Appraisers have "an abundant respect for the guests" and their hopes of finding a treasure. There are few who get the hoped-for payoff. Flanigan said probably only 75 out of every 10,000 to 15,000 objects the appraisers see turn out out have unusual value.

"It's like panning for gold," he said. "It's just so rare. It's as tough as nails."

Even though "90 percent of them couldn't dine out that night" on what their objects are worth, the contacts between the experts and the visitors stays positive and friendly because of the respect with which guests are treated.

He also values the sharing of information among the show's many experts.

"One of the great things that makes Roadshow work," he said, "is that you have the wonderful ability to tap into all these great resources. Another reason why I keep doing the show is that I learn much more every season that I give out.

"It's a chance to do what you love to do and it's a chance to do it on a bigger stage."

He is happy that the closeness of the group and the genuine interest of the appraisers hasn't changed from the very humble start (200 people showed up at the inaugural 1996 event in Concord, Mass.,) to the point where an estimated 10,000 people showed up when Roadshow did its Los Angeles event two years later.

Another benefit, Flanigan said, started when the producers added the city of the appraiser to the superimposed name ID shown during each appraisal. To learn that an antiques authority is doing business near a viewer's home prompts customer contacts.

He also mentions that, by doing the show, he has traveled to parts of the country he might not have had reason to visit. A colleague once mentioned he was going to skip an upcoming city "because it was in the middle of nowhere." Flanigan thought otherwise. He looked at a map and planned what he described as genuinely unforgettable side trips to great scenic landmarks within driving distance of that city.

His participation in the series started as gamble. He received what he called "pretty close to a form letter" asking him if he wanted to be part of this show-in-planning. He didn't know how the producers got his name, and they weren't offering a deal he couldn't refuse. He paraphrased the letter from memory:

"Please travel around the country with us at your own expense for this untested program for which you may or may not appear on the air."

He followed the instincts that have led him to uncover many other treasures in his business life, and accepted the invitation. It's a choice he has never regretted.

"As long as they keep asking me back," he said, "I'll keep doing the show."