If you have been charged with careless driving, you face a fine of $50 to $200, up to 15 days in jail, $33 court costs, and 2 points. If there was an accident, a conviction of careless driving can also cause problems for you in civil court, as it would constitute evidence of negligence in a personal injury suit.
However, the state must still prove its case against you. In order to do so, they must show that you drove "carelessly, or without due caution and circumspection, in a manner so as to endanger, or be likely to endanger, a person or property." This is not always easy to prove, and is often charged in conjunction with other offenses, such as DWI, speeding, unsafe lane change, or the like. Get more info here!