Not only is a lawyer a good idea, it's the law. The Sixth Amendment provides that: " In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the state and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the assistance of counsel for his defense."
Historically, a person accused of a crime could be forced to act as his own lawyer which predictably led to convictions because of ignorance of procedures or how to interpret the law and not actual guilt. The Sixth Amendment was designed to bring this to an end. So, the Sixth Amendment applies in criminal prosecutions. In New York, crimes are misdemeanors or felonies. Because desk appearance tickets are typically issued for misdemeanors, a desk appearance ticket signals the start of a criminal prosecution and you need a lawyer. Having representation makes good sense when you consider what's at stake. Even if it's your first arrest, a class A misdemeanor carries a one year jail maximum. Even if you aren't facing jail, any conviction (even to a lesser charge) and even an adjournment in contemplation of dismissal (ACD) can jeopardize employment, lead to a permanent record, prevent international travel, cause immigration problems, and cause civil liability for the same or similar thing you were arrested for. There also the danger of an unforeseen change in your charges. I was in New York City criminal court at 100 Centre Street when I saw someone appear in front of a judge on a desk appearance ticket which charged him with misdemeanor assault. The prosecutor served notice that the case was indicted meaning that a grand jury voted felony charges and the judge set bail. Leave nothing to chance. Don't go to court alone. Go with an attorney who focuses on criminal law and has the proper experience to effectively argue your case.