Ultimately, how often you work with your personal trainer will depend on a variety of personal factors like time, money, etc. Generally speaking though you should be exercising (with a trainer or on your own) between 2-3 times per week, with a minimum of one day of rest between your workouts. When it comes to how often (and at what intensity) you exercise, it will depend on your goals. To determine the best workout program based on your goals, needs, etc., we highly urge you to consult a fitness professional.
Keep in mind that it is possible to work out too often. Excessively challenging your body with physical demands – ‘overtraining’ – can lead to both chronic and acute injuries. Planning adequate rest will help your body adapt to the work and improve.