The decision whether to accept a plea bargain depends on the strength of your case and your comfort level with the risks of trial.
A plea bargain is a deal in a criminal case offered by a prosecutor as an incentive for a defendant to plead guilty before trial. Usually, plea bargaining results in a charge reduction and/or recommendation of a lighter than maximum sentence.
Plea deals allow criminal defendants to avoid the risk of conviction at trial on original (more serious) charges. They also allow prosecutors to save public resources by obtaining guilty pleas in cases that might otherwise go to trial.
Plea bargaining is an important part of our criminal justice system. Approximately 90% of criminal cases in the United States are settled by plea bargain rather than trial. If every criminal case (or even half of the cases) went to trial, the courts would be so overloaded that they would effectively shut down.
There a several types of plea bargains. To demonstrate how they work, consider the plight of "DWI Danny," a fictional client accused of (1) driving drunk with a .175 blood alcohol concentration and (2) improper lane usage.
With charge bargaining, a defendant pleads guilty to a less serious crime than the original charge (the prosecutor reduces Danny's DWI to careless operation in exchange for a plea). With count bargaining, he pleads guilty to fewer counts than originally charged (Danny pleas to DWI and the prosecutor drops improper lane usage). With fact bargaining, a defendant pleads guilty while the prosecutor stipulates to certain facts that will affect punishment (Danny pleas to DWI with his blood alcohol reduced from .175 to .149 to avoid mandatory jail time). Finally, with sentence bargaining, he pleads guilty as charged with an agreement on the sentence he will be given pending judicial approval (Danny pleas to both charges with minimum penalties).
Plea bargaining may offer you an opportunity to reduce the number or severity of your charges and -- more importantly -- lighten your sentence. If conviction is likely and you are risk averse, you should go along with 90% of criminal defendant and strike a plea deal. However, if you are a risk taker who likes your chances of acquittal, embrace the heightened risk/reward of trial instead.