Retainers Explained: Classic, Evergreen, and Flat-Fee Deposits

Few words in legal practice carry as much freight with as little precision as "retainer." Clients use it to mean the check they write to start the engagement. Attorneys use it to mean anything from an advance fee deposit to a monthly availability fee to a flat fee paid up front. The trouble is that these are legally different arrangements, with different trust accounting treatment, different refund obligations, and different ways to get a new attorney in trouble when they're confused.

For a solo attorney, retainers are also the cash flow backbone of the practice: collected properly, they mean you're never financing a client's matter involuntarily. So it's worth getting the vocabulary, the mechanics, and the paperwork exactly right. Here's the guide to how retainers actually work.

One Word, Three Arrangements

Sort every "retainer" you'll encounter into one of three buckets:

• The advance fee deposit (sometimes called a security retainer): money paid up front, held in trust, and billed against as you earn fees. This is what most people mean most of the time, and it's the workhorse of solo practice.
• The classic or "true" retainer: a fee paid not for work but for availability, to reserve your time, or your exclusivity, over a period. It's generally earned when received precisely because it buys the reservation itself, not future services.
• The flat-fee deposit: a fixed price for defined work, paid in advance. Whether it can be treated as earned on receipt or must sit in trust until the work is done varies significantly by state.

The reason the sorting matters is trust accounting. Under Model Rule 1.15, money that is still the client's belongs in your trust account, and money that is yours cannot sit there. Misclassify the retainer and you're either commingling or converting, and both words appear regularly in disciplinary opinions with "new solo attorney" nearby.

The Advance Fee Deposit, Done Right

The mechanics of the standard arrangement are simple and unforgiving. The deposit goes into your client trust account the day it arrives. It remains the client's money. As you perform work, you invoice against it, and only then do earned amounts move to your operating account, with the invoice as the paper trail for every transfer. When the representation ends, anything unearned goes back to the client promptly, an obligation Model Rule 1.16 makes explicit.

Size the deposit honestly. A useful rule of thumb is one to two months of expected work, enough to keep you from becoming the client's creditor, not so much that the number itself kills the engagement. And send the accounting with every invoice: work performed, amount applied, trust balance remaining. Clients trust what they can see, and the running balance is also your early warning system.

The Evergreen Clause: Small Sentence, Enormous Difference

The standard advance deposit has a known failure mode: it runs out, usually at the moment the matter heats up, and the attorney keeps working while the unpaid balance grows. Now you're financing litigation on a handshake, and collections season is coming.

The evergreen retainer fixes this with one engagement letter clause: the client agrees to replenish the deposit to a stated level whenever it falls below a threshold. Billed against monthly and refilled monthly, the deposit never empties, you always hold security for current work, and the client never receives a surprise five-figure invoice, because they've been paying as the work happened.

Two habits make evergreen arrangements work in practice. First, enforce the clause early and politely: the first time a replenishment invoice goes unpaid, pause and have the conversation, because a client who won't refill a $2,500 deposit in month two is telling you something important about month eight. Second, connect the clause to your withdrawal rights in the engagement letter, so the consequence of sustained nonpayment is spelled out before it's ever needed.

Explaining the arrangement to clients is easier than new attorneys fear, because the honest explanation is also the persuasive one: "The deposit isn't my money, it's yours, held in a trust account. I bill against it monthly and send you an accounting, and whatever isn't earned when we finish comes back to you. When it runs low, you'll top it up, which keeps you from ever facing one giant bill." Clients hear fairness and transparency; you get security. Say it at the consultation, put the same words in the engagement letter, and the money conversation stops being awkward for the rest of the matter.

True Retainers and Flat-Fee Deposits: Handle With State-Specific Care

The classic availability retainer is rarer in solo practice but real: a business client pays monthly to guarantee your availability and conflict you out of representing their adversaries. Because it purchases the reservation itself, it's generally earned on receipt and goes to operating, not trust. The caveats: it must be genuine (actually buying availability, not prepaying for work with a fancier name), it remains subject to the overall reasonableness requirement of Model Rule 1.5, and some states scrutinize or restrict nonrefundable characterizations. Label it precisely in the engagement letter and don't use the structure casually.

Flat-fee deposits are the trap for the unwary, because states genuinely differ: some treat advance flat fees as client money that stays in trust until earned, some allow earned-on-receipt treatment with specific written disclosures, and most disapprove of the word "nonrefundable" standing alone, since even an earned-on-receipt fee can require partial refund if the representation ends early. The safe pattern for a new solo: put advance flat fees in trust, define milestones in the engagement letter (signing, filing, hearing, completion), move money as milestones are reached, and check your state's specific rule before doing anything cleverer.

The Setup That Makes All of This Routine

Retainer discipline is a systems problem, not a virtue problem. Configure your practice management platform so trust and operating are cleanly separated, replenishment invoices generate automatically when balances cross the threshold, and every invoice shows the trust accounting. Keep your engagement letter templates matched to each arrangement, with the retainer type named, the replenishment clause spelled out, and the refund treatment stated plainly. The ABA's model trust account record rules describe the documentation to keep behind it all.

And when you hit the genuinely state-specific questions, whether your flat fees can be earned on receipt, how your jurisdiction views true retainers, what replenishment thresholds other solos actually use, ask people who practice under the same rules. Overture's private forums give you a place to put those questions to experienced attorneys candidly, before the answer costs you a disciplinary consultation.

The Bottom Line

Retainers reward precision. Know which of the three arrangements you're offering, put the right one in the engagement letter by its right name, keep client money in trust until it's earned, and let an evergreen clause keep the economics honest for both sides. The attorneys who get retainers right never think about them; the ones who don't think about little else during collections season.

A well-funded practice also refers with a clearer head. Join Overture for free for the network that handles the matters your retainer structure can't, and a community of attorneys for the fee questions your state bar's FAQ never quite answers.