They usually recommend 40-50 hours. But you don't really need that much time. Just practice long enough until you feel comfortable and confident about taking the road test. I took lessons for about a month before taking the road test. I've had my license for about a year now and haven't had any incidents, no crashes, no tickets, never been pulled over by a cop. Just remember that for the test, they watch everything you do, including the way you hold the wheel. Make sure you're doing everything the "proper way" and then once you pass you won't have to worry about any of that anymore.