About 10-15 min/side
In the first days after delivery, it will likely take a while for your breast milk to come in.
Once your milk is in, most babies will effectively be able to nurse about 10-15 minutes per breast for each feeding
. As your baby gets older, he/she may become more efficient & able to get the milk out faster than that. Also, some babies nurse from only one side at a time- if so, 20 minutes may suffice.