Depends where you are going and if you are familiar with the testing place. I would arrive an hour early to be able to peacefully sign in, go through security, have a snack, go to the bathroom, and honestly just have a 10 minutes of relaxing before the exam starts. You don't want to be stressing over small things when you got the DAT coming at you.
Also call ahead to make sure your forms of ID are good enough, you honestly never know what can happen.