When my baby was 4 months old, I still fed her at night as I started work and wanted to keep the milk supply. Since I fed her on my bed and went to sleep when she was feeding, therefore I still had sufficient sleep. My baby started to 介夜奶 when she is around 6 months when I wanted her to have better sleeping pattern. I guess it's depends on 1) how ready your baby is to quit the night feed, 2) how well you are coping and continuing feeding her at night as it can get v. tiring if you are a working mother. Hope it helps.