The ultra-wealthy have a peculiar set of wealth management needs different from most investors, but like most investors, they too are fallible and make mistakes, according to financial professionals working with such clients.

One of their biggest mistakes, family office professionals tell Bloomberg, is not letting the family office do its job. Stewart Kesmodel, head of the global family office for the Americas at UBS, tells the news service that some families try to exercise cost control by running “a bare-bones crew.” This could instead create inefficiencies, such as the case with one client who severed ties with Wall Street completely and built “their entire investment team from scratch,” he tells Bloomberg.

And some may be open to getting guidance but then continue doing what they did before, “even though it’s detrimental to their goals and objectives,” Kesmodel tells the news service.

Keith Bloomfield, CEO of Forbes Family Trust, says the most desirable investments are also some of the most complex, requiring “patience, liquidity management, and specialized advisors,” he tells Bloomberg.

“The world’s most prominent families may have all of those in spades, but without a sophisticated family office to orchestrate all of those, they are likely to see subpar results,” Bloomfield tells the news service.

Leo Hindery, managing partner at Intermedia Partners, tells Bloomberg he tries to stay out of areas in which he has no relevant expertise. Not so for some wealth families, however.

“I have a friend who oversees investments for a very large multigenerational family office in California, and he tells me about the family members constantly jumping in with ideas in areas where they don’t have expertise,” he tells the news service. “I don’t know how he ever optimizes outcomes.”

The ultra-rich make plenty of other blunders, experts tell Bloomberg. Some fail to have a family governance structure, which sabotages their efforts to build or even maintain wealth, Avy Stein, co-founder Cresset Capital Management, tells the news service.

Others don’t take cybersecurity seriously enough, Elizabeth Glasgow, partner at Venable LLP, tells Bloomberg.

And some families are too stuck on portfolio returns instead of what they want to accomplish with their wealth, Rich Henry, senior vice president and managing director at PNC Financial Services Group’s Hawthorn, tells the news service.

Many families try to get into charitable donations without understanding the needs of those they want to help, Kris Putnam-Walkerly, president of Putnam Consulting Group, tells Bloomberg. Matthew Weatherley-White, co-founder and impact investing specialist at the Caprock Group, says some ultra-wealthy clients are so focused on social-impact statements that they fail to do their due diligence on investments in the area, according to the news service.

And Von Sanborn, partner at Day Pitney LLP, says too many art lovers are collectors rather than investors in art and often end up making less-informed decisions, Bloomberg writes.

Finally, some families are too concerned with tax management, which eventually costs them dearly, D. Stephen Antion, partner at Winston & Strawn LLP, tells the news service.