But today, Lipman says, “as people in their late thirties and early forties start collecting, we're seeing a lot of hip hop, punk and grunge memorabilia becoming very, very collectible. Fifteen years ago, you could have gotten it for a song.”

Given that many celebrity items are truly one of a kind, appraisers and auction houses sometimes dig deep to determine valuations, says Brian Kathenes, managing partner of National Appraisal Consultants and a certified member of the International Society of Appraisers. 

“We always try to find out what the collector paid for the item and whether it was sold at auction or in a private sale,” he explains. “The price paid is the best comparable. If we don't have that, and if there's nothing else like the item, we'll look for other iconic items in a parallel market, which is an accepted methodology.”

Unusual collection items can also present a challenge when it comes to structuring an insurance policy, says Julie Sherlock, assistant vice president and premiere underwriting manager for Ace Private Wealth Services—but fortunately, “there are appraisers for everything, and we rely on those experts to help us.” Once a value and limits have been established to determine coverage rates, she adds, “we ask the same questions we always do about where an item is stored and what the potential catastrophic exposures are.”

Ironically, while savvy collectors are attuned to the need to purchase specialty coverage for their celebrity-related ephemera, film stars, musicians, athletes and other public figures often don't realize the potential value of their possessions and the need to protect them. “It's just their stuff—their trophies, their uniforms—and they're just sitting on it,” Lipman observes, adding that this presents a good opportunity for insurance agents and brokers to educate these clients about appropriate coverage. “I've seen quite a few insurance companies proactively approaching their clients about it.”