In The Run of His Life: The People v. O.J. Simpson, Jeffrey Toobin distills the essence of lawyers who represent criminals:

Technically, the space where the attorneys gathered was not really [Robert] Shapiro’s at all. Because he didn’t have a conference room of his own, Shapiro had borrowed one from the large law firm where he rented space. Under the pressures of the Simpson case, Shapiro would come to use it so often that he eventually broke down and added the conference room to his sublet arrangement. Like most criminal defense attorneys, even the best known, Shapiro ran a lean business operation. He had a secretary and two young lawyers as associates. Every month, Shapiro wrote out by hand all the checks to cover his office expenses, including payroll. In recent years, he had had no trouble meeting that payroll—business was good—but Shapiro was ever mindful of the criminal defense attorney’s dilemma: Successful though one may be, one can never count on repeat business. An unending supply of new clients must always be found. The quest for clients—his own and his friends’—was an important subtext for the gathering he had assembled this summer afternoon.

. . .

The high end of criminal defense law operates almost entirely on a referral basis—that is, lawyers are hired because other lawyers recommend them—and Shapiro knew that his guests on this Saturday would not soon forget he had included them in this extraordinary session. A profitable referral to Shapiro would be the appropriate gesture of gratitude.

Criminal defense lawyers cannot count on repeat business, and much insight flows from this fact. Criminal defense lawyers need a constant stream of new clients, which means they generally rely on referrals. (In New York, criminal lawyers can also earn money by becoming “18B lawyers”–they are compensated for representing indigent clients charged with criminal offenses.)

It is also interesting to note that even someone doing high-end criminal defense can sublease space from a large law firm and have just a secretary and two associate attorneys.