There's no reason why you shouldn't show up and take your driving test. But if you decide to walk in without an appointment, you'll end up waiting long hours to make your exam request. The easier way is to schedule an appointment prior to visiting your local DMV.
You can take the written test anytime. There is no wait for that. The driving course on the other hand you MUST have an appointment for this or they will ask you to make one or turn you away because you don't have an appointment.
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