Bottle Nipple Sizes

Hey all,

I exclusively pump and have been feeding my baby since birth using the avent bottles with the newborn nipples (size 1) they come with. The philips website suggests using size 1 for exclusively bottle fed babies 0-1 months or breastfed babies 0-3 months.

My little one is nearing 3 months old and I bought the next size nipple a while ago but didn’t start using it, despite the manufacturers recommendation, because he was still having issues with milk dribbling out the sides of his mouth. I took this to mean the milk was flowing too quickly for him. He no longer seems to have issues with milk pooling in his mouth but doesn’t yet seem frustrated with the flow of the nipple. Should I move up to the size 2 nipples or keep using size 1 until it seems like he’s having an issue with the slow flow?