"The ADV questions don't pretend to ask every single thing that may be disclosable to clients," said MarketCounsel's Hamburger.
Reports that include customer disputes with investment advisor representatives are available on the SEC website.
Investors should also ask about the number of clients who have left the firm in the past year, and ask for referrals to former clients, Kuechler said.
"At the end of the day, whether a person is a broker or whether they're an RIA, I think that 99 percent of us really want to do the right thing by our clients," said Susan John, an advisor based in Wolfeboro, New Hampshire, and chair of the National Association of Personal Financial Advisors.
"Of course, there's always that 1 percent."