"Billing was the lifeblood of the firm. Everything revolved around it. Promotions, raises, bonuses, survival, success," John Grisham writes in his 1991 novel The Firm.

Decades later, fees are still hardwired into the fabric of Big Law where time is tallied and traded in six-minute and 15-minute intervals. While there has been a slow pivot toward alternative fee arrangements in the last decade, many firms still cling to the tenet of the billable hour, even as artificial intelligence reimagines its contours.