I have no idea and I scoured The Baby Book by Dr. Sears and it doesn't have any type of feeding schedule on it.

My mom just said, "when he's hungry" - well d'oh! But sometimes he doesn't show signs of hunger, or he takes long naps or we're out and about and it's been longer than I realize and he was content to sleep/watch/observe. He has gone as long as 4 hours during the day between feedings, but usually I TRY to feed him ever 2-3 hours. That's how often I fed him as a NB though. How often do you feed your 4 mos old?