Last year, Above the Law declared this the era of mandatory retirement for law firm lawyers, tracking the popularity of such policies back to the 1980s. That's not to say it never comes under fire. In fact, some U.S. law firms have paid dearly for having such policies.  

Most recently, in April 2012, Kelley Drye & Warren agreed to pay labor and employment partner Eugene D'Ablemont $574,000 as part of a consent decree with the Equal Employment Opportunity Commission (EEOC) to settle an age discrimination lawsuit it brought on D'Ablemont's behalf. The suit concerned a policy in the firm's partnership agreement requiring equity partners to give up their equity stakes for a fixed salary at age 70. 

The payment to D'Ablemont, who was 82 at the time of the settlement, covers work he performed from 2001 to 2011. Shortly after the EEOC sued Kelley Drye in 2010, the firm dropped the mandatory retirement policy, but the EEOC continued to pursue the case. The Kelley Drye consent decree also provided D'Ablemont with 12 percent of the fees he collects going forward.

That's a drop in the bucket compared to the $27.5 million that Sidley Austin paid to settle an EEOC suit that alleged the firm demoted (i.e., de-equitized) 32 partners solely on the basis of their age. Sidley Austin had argued in litigation that the partners were owners rather than employees subject to the Age Discrimination in Employment Act (ADEA). The EEOC countered that Sidley treated the partners at issue in the suit as employees for ADEA purposes.