“It may seem safer to put this off for another year or two or three out,” said John A. Warnick, founder of the Purposeful Planning Institute. “It’s always difficult to start it. Part of what contributes to that procrastination is a fear that disclosure of information might disincentive children or grandchildren.”

That belief, advisers said, is more often a myth than the reality within a family.

“The myth is usually that their kids are going to be ruined by the money, that money will be what ruins everyone,” Ms. Moss said. “I just don’t see that as often as I see mismanaged expectations and a lack of training and preparation. Bad decisions get made because they don’t know any different.”

Some advisers suggest that one way to start family conversations is to focus on values, rather than financial assets, at least in the beginning. They say that transmitting those values will make passing along financial assets easier.

“What we see consistently in families that can pass along assets is it’s really about passing along values and legacy,” said Dune Thorne , head of the Northeast region at Brown Advisory, an investment adviser for multigenerational families and business owners. “It’s the values that make them successful, not the actual assets. And if the values transfer, the assets pass more easily.”

Some families, as a matter of tradition or necessity, have a history of talking openly and making decisions together. The Carvajal family started in the printing business in Cali, Colombia, in 1904 and is now a multibillion-dollar, sixth-generation family with business interests that stretch throughout Latin America up to the United States border.

“The family members had a habit of discussing things very openly,” said Manuel Jose Carvajal, 64, and part of the fourth generation. “Some would have discussions, sometimes very heated, but people would abide by the decisions. There was a mixture of family and business things that were talked about within the family, but never outside.”

But as the family increased in size and spread geographically — it now numbers 300 members who live throughout Latin America, the United States and Europe — family leaders moved to make conversations almost a requirement. Like the Eddys, the Carvajals created a family council in the 1990s for all members to have a voice, but particularly for the female members who had not worked in the company and lacked the same access to information as their male cousins.