If you have ANY previous record it could affect the sentencing on your case, specifically if you have been charged and convicted of the same crime before any new arrest will likely lead to greater sentencing.
generally, sentencing can vary on the same crime depending on the circumstances. A DWI first offense in NY, with no accident, will likely lead to a plea to a misdemeanor and no jail or probation. An accident or injury will generally change that, if there have been previous arrests for DWI it could even be chargeable as a felony.
while this is the least talked about factor, your defense attorney will play a great role in what offers the DA gives you on your cases and what the ultimate outcome of your case will be. A more respected, established, attorney will likely be able to accomplish better results.