NEW YORK (CNNMoney.com) -- Once a year, baseball-card collectors gather for the granddaddy of all sports collectible conventions - the National Sports Collectors Convention.

Currently underway in Anaheim, Calif., the four-day event will not only be a place for collectors to haggle over the value of their Lou Gehrigs and Jackie Robinsons, there's bound to be a few collectors who reflect on how the hobby took a nosedive during the 1990s.

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Andy Madec, a dealer based in Camarillo, Calif., remembers that time vividly.

Up until the late 1980s and early 1990s, collectors were living in a golden age, says Madec - returns of 20 percent in just six months were not unheard of. But that was until the card companies tried to get in on the fun. Flooding the market with multiple versions of new cards, the manufacturers drove down card values.

"It just got too out of hand," says Madec, who runs his own firm, Andy Madec Sports Cards Inc. "It turned people off."

Even in good times, collecting is a tough hobby. It boils down to a couple of simple principles -- how many there are and what kind of condition the card is in.

But there is a lot of fickleness too, says Scott Kelnhofer, editor of Card Trade, the monthly trade journal for the sports collection industry

Take Cal Ripken Jr.'s 1982 Topps rookie card. In 1996, the year after Ripken broke Lou Gehrig's record for number of most consecutive games played, a card in mint condition that had not been professionally appraised would have sold for $90. But with Ripken's achievement faded from the minds of collectors, that same ungraded card would only fetch $40 today.

"It's a tricky thing," Kelnhofer says.

The market has been bouncing back, particularly vintage cards, those that date backs 25 years or more. "The vintage market is still the place for people to get involved purely from an investment standpoint," says Kelnhofer. "There's always buyers and sellers for that material."

Rookie cards of players like Mickey Mantle, who typified the golden era of baseball, are always in high demand among older collectors.

Then there are the cards from the 1970s and 1980s, which predate the card explosion, that some experts like Kelnhofer say could experience the next wave of popularity.

Cards dating back to the turn of the 20th century that were produced as promotional items for ice cream, candy and tobacco companies are some of the hottest cards on the market right now, according to collectors.

In fact, the fabled Honus Wagner card, which was produced by the Sweet Caporal Cigarette Company in 1909, is currently the most expensive card in existence, worth a cool $1.265 million. (See the most valuable cards.)

Even though the hobby struggles to bring young collectors into the fold, there have been some promising signs for baseball card collecting as of late.

Earlier this year, the Major League Baseball Players Association lent their assistance, cutting in half the number of licenses it offers to card manufacturers in an effort to rid the glut of new cards on the market.

And in June, Major League Baseball and the players' association teamed up with card manufacturers Topps and Upper Deck to launch the first ever National Baseball Card Day, giving out 500,000 card packs at hobby shops and retailers nationwide in an effort to promote the hobby.

Dealers like Stephen Dickler, who runs SD Trading, located just outside of Philadelphia, says moves such as this could work, but it's too early to tell. "There's no guarantee it will happen," says Dickler. "The questions are still out there as to whether it will have an impact or not."

But many in the industry, like Madec, who is currently attending the National Sports Collectors Convention, is certain that is there is a future for this enduring hobby, despite its setbacks in recent years. "This market has incredible potential," he says. "Investors just need to hear it's safe to go back in."

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