The fee agreement is the only document in an impaired-driving case that you get to negotiate before anything happens, and it is usually the one people read least carefully, because they are reading it in a lobby, on a phone, in the week after an arrest when sleep is short and the retainer feels like the price of relief. Slow down for twenty minutes. The agreement decides what you are buying, what you are not buying, and what happens to your money if the case ends early or goes further than either of you expected.
Flat fee and hourly are answers to different questions
A flat fee prices the outcome of a defined stage: arraignment through disposition, say, or everything short of a jury trial. It transfers risk to the attorney, who eats the hours if the prosecutor is slow or the discovery is a mess, and it gives you a number you can plan around. Hourly billing prices the effort instead, and it can be cheaper on a case that resolves in two settings, more expensive on a case that grinds. What a careful reader checks is not which model is better in the abstract, but where the flat fee's boundary sits and what the hourly rate applies to: attorney time only, or paralegal and travel and court waiting time as well, and in what increments those are billed.
The quoted number is a scope, not a ceiling
Most quotes on a first-offense case cover the ordinary path: entry of appearance, discovery review, negotiation with the prosecutor, and a plea or a dismissal. The things that make a case expensive usually sit outside that scope, and the agreement will say so in a sentence you can skim past. Contested motion hearings, a suppression hearing on the stop or the breath instrument, an independent expert to review calibration and maintenance records for the machine, a toxicologist, trial itself, and any appeal are commonly billed separately or trigger a second flat fee. Ask directly what a suppression hearing adds, what a trial fee would be, and whether expert costs pass through at cost or with a markup.
Retainers, trust accounts, and the word earned
Money you pay up front generally goes into a client trust account, which is separate from the firm's operating account, and it stays yours until it is earned under the terms you signed. Under an hourly arrangement, the attorney draws against that balance as work is performed and sends you a statement showing what was withdrawn and why. Under a flat fee, the agreement should say when the fee is earned: on signing, in stages tied to work completed, or on conclusion. That single clause determines what you get back if you change lawyers in week three, and state rules in most jurisdictions require the agreement to spell it out. If a payment plan is involved and it runs through a third-party lender or a card, note that consumer credit terms are overseen by the Consumer Financial Protection Bureau and are a separate contract from the fee agreement itself.
Making two differently worded quotes comparable
One firm says thirty-five hundred, all-inclusive through plea. Another says twenty-five hundred plus costs, with trial quoted separately. Those are not comparable until you normalize them, and the way to normalize them is to price the same four events under each: a routine plea, a contested suppression hearing, a one-day bench trial, and a case where the state's expert has to be cross-examined. Write those four numbers down for each firm. Then check the smaller items that move the total: filing and subpoena costs, transcript fees, whether the license hearing before the state motor vehicle agency is inside the fee or billed apart, and whether a second office consultation costs anything.
Clauses worth a second read
Look for the withdrawal provision, which says when the attorney may stop representing you and what happens to unearned money then. Look for the communication term, which sometimes commits the firm to a response window. Look for the scope line naming the specific charges and the specific court, because an added charge, a probation violation, or a companion case in another county is usually new work at a new price. Anything the lawyer promised out loud belongs in writing before signatures.
A good agreement makes the lawyer's obligations legible and gives you a document to hold up later. If a clause is ambiguous, ask for it to be redrafted; firms that do this work routinely will amend without complaint, and the redraft tells you something about how the rest of the representation will go.