Hmm... I remember that by 6 weeks, Colin was going at least 5 hours at least once during the night. But I didn't let him go that long during the day (I woke him every 3-4 hours) because I didn't want him to get his days and nights mixed up. I believe that the guideline is 8-12 nursings (for an exclusively bf'd baby), and Colin was always on the low side of that. In fact, by 6 weeks, I believe he was nursing about 7 times a day.
The most important thing is to count his wet and dirty diapers. If there is enough coming out the back end, then there is enough going in the front end!