For Hourly Billing, the Baseline Is Actual Time
ABA Formal Opinion 512 is unusually concrete on this point. A lawyer billing by the hour must bill the time actually spent. If a generative-AI tool produces a draft in minutes, the lawyer can charge for the time spent operating the tool and for the time reasonably spent reviewing, correcting, and completing the work—not for the historical amount of time the task used to require.
That rule prevents a hidden efficiency surcharge. A client who agreed to hourly billing bought professional time under the engagement terms, not an entitlement for the lawyer to recreate yesterday’s inefficiency on today’s invoice.
Review Time Is Still Real Legal Work
The opposite mistake is to treat AI generation as the whole task. In patent practice, a generated claim set, Office Action response, FTO chart, or invalidity analysis still requires verification of sources, claim scope, legal standards, support, procedural posture, and strategic consequences.
If the model creates a draft in ten minutes but a senior practitioner spends ninety minutes validating and restructuring it, those ninety minutes are not “AI overhead.” They are the part of the work where professional responsibility and judgment sit.
AI Tool Costs Are Not a Blank Check
Formal Opinion 512 also distinguishes fees from expenses. A firm should not invent an arbitrary AI surcharge. Depending on the tool and engagement, some AI costs may be treated as overhead; an identifiable matter-specific out-of-pocket expense may be chargeable if reasonable and properly disclosed.
Efficiency Creates Pressure to Change the Pricing Model
The deeper business issue is that AI makes time a weaker proxy for value. If experienced professionals can solve a recurring problem faster because they have better systems, templates, models, and judgment, pure hourly billing can punish efficiency.
That creates room for clearly scoped fixed fees, phased fees, subscriptions, or other structures where permitted and reasonable. The ethics question does not disappear: the basis of the fee must be communicated, and the fee must remain reasonable. But the commercial conversation can move from “How many hours did this take?” toward “What decision, risk reduction, or deliverable is being purchased?”
Patent Work Makes the Tension Obvious
Consider a high-risk U.S. patent opinion. The client is not paying for keystrokes. It is paying for the correct patent family, the correct claim construction, a defensible infringement analysis, a reliable validity assessment, and a work product that can support a real business decision. AI may reduce the time needed to collect and organize the record, but it does not eliminate the value of being right when the conclusion matters.
Takeaway
For an hourly engagement, AI efficiency should generally reduce billed hours because actual time remains the billing unit. For the profession more broadly, however, AI is a reason to rethink whether time should remain the dominant unit of value. The sustainable premium will move toward judgment, verification, risk ownership, and clearly defined outcomes.