The evidence presented in a drunk driving case, including field sobriety tests, affects the DWI defense. Those facing these kinds of accusations should be sure to fully understand all of their rights and obligations under the law before deciding how to proceed when charged with DWI.
With each conviction of driving while under the influence of drugs or alcohol, the penalties increase. You lose your license, you forfeit your car, you get probation and maybe even jail time if you don't learn your lesson after a few arrests. By that time, your choices boil down to trial or plea bargain, and mitigate the extent of your punishment as much as possible.