How much will my baby sleep, and how can I tell if he is sleeping too much?

As what Idza mentioned, newborns tend to sleep a lot and their wakings are driven by basic needs. As long as your baby is waking up for feedings, you shouldn't be too worried. Consult a doctor when you notice your baby has not been waking up for feedings or is having a fever. He/she may be having an infection.