The main reason anyone would ask that question is because they have been charged with some form of DUI (driving under the influence) or DWI (driving while intoxicated). If this sounds like you or someone you know you need to hire a lawyer as quickly as possible.
There are several reason why you need a qualified DUI lawyer working hard for you. Primarily they will know your legal rights in regard to the specific charge against you. Thus, they will be able to help prevent you from self-incriminating yourself or any other mistakes you are likely to make.
Moreover, if the charge is a serious one, which hopefully it is not, they will know how to defend you in court. You need the experience of a good DUI lawyer because they understand how to talk to judges, juries and the prosecution. And once again they will know the law far more throughly than you will, given their years of legal experience.
Probably the most common argument against hiring a DUI lawyer is that they are expensive. Well this is a valid point any good DUI attorney is going to be expensive, but that is because of the value they provide. For example, how much would you pay to avoid going to jail even for a few months. For many people the cost of the DUI lawyer when compared to the potential fines and/or jail time of not; find that hiring one is a good investment on their part.
There are however some common misconceptions about what a skilled DUI lawyer can and cannot do. Most importantly they are not miracle workers. If you have driven drunk and killed someone there is no way that you are going to get away with only a fine. People often see shows such as Law and Order and think that lawyers can get people out any situation.
The truth is that if you are guilty of killing or seriously injuring some one while DUI you will face jail time. However, even in these cases it makes sense to hire a good DUI lawyer because they may be able to get your sentence reduced somewhat, especially if you plead guilty.
The situation where DUI lawyers work best though is for first time offenders. They can ensure that the fines and/or jail time will be as minimal as possible. Think of them as your get out of jail free card, that you can only use once. The more serious the DUI offense or the more DUI convictions you have the less leeway a DUI lawyer will have with your case.
Thus, if you have been charged with a DUI or DWI you need a lawyer on your case. Just remember that they are not miracle workers. They have to work with the particularities of your case and history. In the end though you will be glad you did. Better yet, don't drink and drive in the first place and you will never have to ask this question again.