How to distinguish a partner at a top British law firm versus an American firm? The U.S. partner will generally bill more hours, earn more money, take less vacation, have more personal, rather than institutional, client relationships—and have more gray hair, or so say the stereotypes.

While partners at U.S. firms routinely work into their late 60s and beyond—Wachtell, Lipton, Rosen & Katz founders Herbert Wachtell and Martin Lipton are still going strong at 84 and 85, respectively—those at top U.K. firms are usually out the door by the time they’re 55.