Oh, it's a tricky one! I wondered about this too. In the early days, I woke Natalie every three hours for a feed during the day, and let her go for 5-6 hours before waking her at night. Although, as Sammi said, if your bub is feeding more often during the day he may be getting enough for him to sleep for longer at night... I'd say, do what makes you comfortable. If you want to have the sleep while you can, do it. If you don't think your baby is ready to sleep through, wake him. It's your call.