Hi - my name is XXXXX XXXXX I'm a Criminal
Law litigation attorney here to assist you.
No, a lawyer is not absolutely necessary, but it is highly recommended. A judge is going to likewise recommend that you employ an attorney in order to make sure you are defended and give yourself a chance to defeat the offense because the 3rd conviction is a felony and will send you to the state pen.
Thus, if there's a chance you can find some technicality to beat the offense, it is certainly in your best interest to do so. There are 1000's of little nuances that DUI defense attorneys key in on to defend the case. For instance, if the mouthpiece wasn't changed out between blowing in the intoxilyzer machine, that could cause the results to be incorrect, or if the officer didn't observe you for 15-20 minutes before administering the test, that could be grounds, or if the ticket doesn't bear the officer's signature/name, or if the ticket doesn't provide the date of the court
hearing, etc., it could be grounds to throw the ticket out.
The unfortunate thing is that you don't really know what defense may be available until you have an attorney review your case; however, doing so will cost a lot of money to do so.
Thus, it is certainly recommended to hire an attorney, but it is not required.