The billable hour hasn’t been around that long, relative to the centuries-long history of the legal profession. Years ago, lawyers would bill at the conclusion of a legal matter based on the lawyer’s view of the value to the client of the advice and assistance provided. Or the weight of the file, as the joke goes.
Sometime in the middle of the 20th century, law firms began to track the number of hours being spent on a file as a way of measuring whether the fees being charged were proportionate to the use of firm resources. That soon evolved into a way of measuring associate and partner performance and then into a way of billing clients. As often happens, metrics began to trump professionalism.
The concept of “billable hours targets” developed which required that associates bill a certain number of hours in a year in order to be considered for performance bonuses and advancement. Targets gradually increased over the years and the pressure to bill more time increased as well. Now, many firms may have stated billable goals of 1,800 or so a year, but the associates who work there will tell you that 2,000 is truly the minimum.