You have been charged with a crime. Do you need a criminal defense attorney? That depends on how serious the crime. There is a way to determine just how serious your situation is by looking at a few key points. Then you can decide if you want and qualify for a public defender or if you are able to hire your own lawyer.
The Number of Your Charges
Are you charged with just one crime or several crimes? Being charged with several crimes tends to be more serious than being charged with a single crime, but there are a few crimes serious enough that being charged with just one of those crimes puts you in a position that will threaten the rest of your life. For example, speeding away from police and having marijuana in your car is bad, and certainly far worse than just running a red light, but it is not as serious as being charged with murder. Your lawyer will look at your charge or charges and let you know if you are looking at jail time or at fines and community service.
The Nature of Your Charges
No crime is "victimless," but there are certainly crimes that could be categorized as less hurtful or harmful to others. Being accused of domestic violence is often less than being accused of assault with a deadly weapon or rape. Being charged with accomplice to a robbery is less severe than being charged with robbery with an assault weapon. (You get the idea.) The more severe the nature of your charges, the more you should want to have a lawyer defend you. Whether you did it or not, the important factor here is that you still get the right to a defense by attorney.
The Potential Punishment
In states where the death penalty is still a possibility for certain crimes, you want to avoid that punishment when you are charged with a crime where that punishment is possible. Life sentences for certain criminal charges are also something to avoid, if that includes the charges brought against you. If the punishment is so harsh that you cannot imagine serving it or having the punishment executed upon you, you need a lawyer. In general, it is good to have a lawyer anyway. In practice, you want a criminal defense attorney for all of the above, especially if you are innocent of the accused crimes.