On Richard Rosenbaum’s first day as CEO at Greenberg Traurig in 2010, he started talking about who his own successor would be.

“Some people actually said, ‘You have only been at this job a day, why are you thinking of this?’ ” said Rosenbaum, 59. “From the first day I had this position, I considered one of the most important things the future of the firm and how the firm would be operated after my time was up.”