Breastfeeding 3.5 mo old

How long does your 3-4 month old go between feedings? I've had a super easy breastfeeding relationship with my son. From the very beginning he would only feed on one side but fed like a champ because he put on weight like crazy. He had one time where he didn't poop for 11 days so I started feeding him on both sides just to see if more milk would make him go. Which it did. We've continued feeding on both sides about every 3 hours but sometimes I feel like he really isn't interested and could probably go 4 hours. I just thought it was a bit early for him to go that long already.