Through 32 years of marriage, Norma Canelas-Roth and William Roth have amassed an art collection rich in textiles, beadwork and headdresses from Africa, Asia and the South Pacific. They own silk robes from the Qing dynasty. Their trove of more than 1,500 headdresses includes one festooned with feathers from the cassowary and other exotic birds. Another contains the entire mane of a lion.

The collection—an estimated 15,000 pieces in all—reflects more than three decades of frenzied, passionate pursuit. Yet for most of that time the Roths (she is 64, he is 70) gave little thought to how they wanted their art to be dispersed when they die. And they’re not alone. Many art lovers never consider their million-dollar-plus collections in their estate plans. Big mistake. If you’ve spent a lifetime assembling a museum-worthy collection, you’ll need a strategic plan for its orderly succession. Says Peggy Hollander, the founder of The Succession Group in Coral Gables, Florida, “Recognizing its value and planning for it is incumbent upon the art collector.”

Of course, you can’t recognize the value of art without first confirming its authenticity. Karl Schweizer, the head of art banking for UBS, the Swiss financial conglomerate, believes the art world too often falls short on accountability. Before buying any work of art, Schweizer says, a collector should check with the Art Loss Register, a global clearinghouse of legitimately owned as well as stolen and forged art. “If everybody speaks about art as an investment, they should first do their homework to know what they buy, to know what they have, before you discuss anything else,” says Schweizer. “A piece that does not have a proper background is not sellable.”

Once you can account for your art’s provenance, you’re ready to plot its eventual distribution in your estate plan. You’ll need to assemble a team of trusted advisors—a lawyer, accountant and financial planner, for starters—who can help you dispose of your art in a way that is meaningful and financially sound for you and your heirs. Michael Mendelsohn, founder of Briddge Art Strategies Ltd., an art succession planning firm in Purchase, New York, says that a piece of art mishandled in the estate planning process could lose as much as 70 percent of its value—through a collector’s failure to mitigate estate taxes, say, or a poorly conceived sale at auction. “The reason that happens is a lack of planning,” says Mendelsohn, who recently published Life is Short, Art is Long (Wealth Management Press, 2006) to guide collectors in long-term thinking about their art.

Collectors have three basic options: Leave your art with your family, donate it to a museum or other charity or sell it outright. Each choice is rife with legal and tax implications that will require help from your advisory team.