Do I need a lawyer for my DUI case?
You are not required to hire a lawyer or to accept assistance from a public defender if facing a DUI. That may an enticing thought to save yourself the thousands of dollars charged by private DUI lawyers or to avoid the substantial reimbursement fee charged by counties for having a public defender (if you don't fully qualify as indigent).
Do you 100% need a lawyer? It depends. I'm pretty sure that I'm one of the very few lawyers out there who would say that it's not ALWAYS necessary. If you're someone who simply wants to accept responsibility early by pleading guilty to avoid any legal fees or the potential of a drawn-out process, then it's certainly possible that you could resolve your case and end up with a punishment similar or identical to what you would have received with the assistance of a lawyer. In other words, it could be a reasonable option under the right circumstances.
But if you just go in and plead guilty, you're assuming that the DA's evidence is strong enough to surely convict you and that you'll be sentenced to a standard minimal punishment. That may be the case, but to play it safe, even if you feel you're totally guilty, you still may have a viable legal defense or at least avenues to negotiate your case for lesser punishment. In other words, before you face your case completely alone, the smarter move is to have a lawyer at least look over the evidence first.
Now, if you're serious at all about actually fighting your case to trial, then hands down you'll need a lawyer. I would not do that alone (unless perhaps you're a DUI lawyer yourself). First of all, a DUI lawyer will know how to properly review the evidence to spot weaknesses to attack in the prosecution's case.
Secondly, defending oneself in court, regardless of the type of case, is very complex. It takes attorneys many years to become even just proficient in the rules of evidence, let alone show signs of mastery in the courtroom. And then there's the law itself. DUI cases can be very scientific and complex. If proceeding to trial, you'll need to quickly learn many very nuanced skills. For example, you'll need to know...
how to file pre-trial motions;
pick a jury that gives you the best chance for success;
how to cross-examine witnesses, such as an expert forensic toxicologist, in addition to the police officers;
how to make proper objections when the DA presents the case;
how to concisely and cogently argue your defense to a jury.
I can go on and on about the nitty-gritty of courtroom litigation, but the bottom line is that you'll be at a major disadvantage to fight your case without legal representation.
Also, as a practical benefit, a privately retained lawyer can attend court on your behalf, so you don't have to miss work or other obligations and can avoid the hassle of court.
If this is a first-time DUI offense and you are interested in representing yourself to save a few thousand dollars, I strongly advise you to at least have a lawyer review your case first. I offer a virtual legal consulting service (to California residents) where I help you obtain and closely review all of the evidence in your case first. I then coach you, if I feel it's appropriate, to resolve your case on your own.