For generations, law firms have sold one thing above all else: time. Lawyers record their work in six-minute units. Billable-hour targets influence performance, promotion and remuneration. Partner economics depend heavily upon leverage — lots of lawyers recording lots of hours.

AI breaks that equation. If legal research that once took eight hours can be completed in thirty minutes, what should the client pay? And who receives the productivity dividend — the law firm, the client or the lawyer?

Time-based billing creates an increasingly obvious paradox. The more efficiently a lawyer solves the client’s problem, the fewer hours there are to bill.

Technology has been challenging this model for years. Digital research replaced libraries, document automation accelerated drafting and outsourcing reduced the cost of routine legal work. Generative AI is different. It can potentially compress hours of research, review and drafting into minutes.

This isn’t merely a question of hourly rates. Law firms have built entire organisational systems around billable time — graduate recruitment, leverage, utilisation, promotion, partner remuneration and profitability. Remove time as the organising principle and you potentially change the economics and structure of the law firm itself.

Fixed fees are one alternative. Retainers are another. Value pricing asks a different question: what was the legal outcome actually worth?

Advice that prevents a $20 million commercial mistake isn’t worth less because an experienced lawyer, assisted by AI, produced it quickly. The time taken to reach the answer was always an imperfect proxy for the value of getting the answer right.

Clients never really wanted hours. They wanted judgement, expertise and outcomes.

AI may not kill the lawyer. It may kill the billable hour.