Billing for AI-Assisted Work in a NJ Small Firm: What RPC 1.5 Actually Permits

A solo attorney in Cherry Hill drafts a demand letter in 22 minutes using an AI writing tool. She used to bill 1.2 hours for the same task. Does she bill the old rate, the actual time, a flat fee, or something else entirely? If she bills the full hour anyway, is that padding? If she slashes the invoice, is she training her clients to expect everything cheaper?

This isn't a hypothetical edge case. It's happening in small NJ firms right now, and most attorneys are improvising answers rather than working from a principled position.

NJ RPC 1.5 requires that a lawyer's fee be reasonable. The rule lists eight factors for evaluating reasonableness, including the time and labor required, the skill involved, and the results obtained. None of those factors were written with AI in mind. That's not a loophole. It's a gap that NJ attorneys need to fill with their own judgment, documented in advance.

The Core Tension

AI compresses time. That's the point. But under a traditional hourly model, time compression is a problem because revenue is directly tied to hours billed. The honest answer is that the hourly model is increasingly strained by AI, and billing practices need to catch up.

Here's the key principle under RPC 1.5: you're billing for value delivered and skill applied, not just clock time. The ABA addressed something adjacent to this in Formal Opinion 512 (2023), which clarified that lawyers may not charge clients separately for AI tool costs in the same way they might pass through travel expenses unless the retainer agreement explicitly allows it. While that opinion isn't NJ Bar guidance, NJ courts and the ACPE have historically treated ABA ethics opinions as persuasive authority.

The practical upshot: you probably can't tack on a separate "AI usage fee" line item without disclosing it. But you can absolutely factor efficiency gains into how you structure fees going forward.

Three Billing Models Worth Considering

Hourly with a floor. Some attorneys set a minimum billing increment per task regardless of how quickly AI helped complete it, justified by the skill required to prompt, review, and validate the output. This is defensible under RPC 1.5 as long as the time actually spent, including review, is logged and the floor isn't inflated beyond reason. Billing 0.5 hours for a task that took 8 minutes of human effort and zero review time would be harder to defend if a fee dispute ever landed in front of a fee arbitration panel.

Value-based or flat fees. AI actually makes flat-fee pricing easier to offer, because your cost per task drops. A flat $350 demand letter is reasonable to the client and profitable to you when AI cuts drafting time by 60 percent. This model is cleaner under RPC 1.5 because it's transparently priced upfront, and it sidesteps the time-padding question entirely. The retainer agreement just needs to describe the scope clearly.

Hybrid. Many small NJ firms are moving to flat fees for discrete deliverables (demand letters, contract reviews, simple motions) while keeping hourly for litigation strategy and court appearances where AI's contribution is marginal. This lets you capture AI efficiency gains on document-heavy work without repricing everything.

What Your Retainer Agreement Should Say

Whatever model you choose, the retainer agreement is where you set expectations. Consider adding a provision that states your firm uses AI-assisted tools to improve efficiency and that fees are set based on the value of the service and the skill required, not solely on time expended. This does two things: it signals transparency to the client (supporting your RPC 1.4 communication obligations), and it protects you if a client later claims they were overcharged because "a computer did it."

You don't need to be defensive about it. Most clients don't care how you produce the work. They care about quality, turnaround, and price. Framing AI as a tool that helps you deliver faster at a fair price is accurate and straightforward.

The Fee Arbitration Risk

NJ has a mandatory fee arbitration program for disputes under $5,000, and optional arbitration above that. If a client ever challenges a fee and your billing records show 0.8 hours billed for a task your own AI tool completed in 11 minutes with light review, you'll want a clear explanation ready. "I billed for the skill involved in reviewing and directing the AI output" is a legitimate answer. "I billed the same as always because I didn't think about it" is not.

Start logging AI-assisted tasks in your time records now, even if you bill flat fees. Note the time spent prompting, reviewing, and editing. That habit protects you and helps you price future work more accurately.

The attorneys who get this right will be more competitive on price, more profitable per hour of actual effort, and better positioned to explain their fees if anyone ever asks.