I’ve always read that milk is produced on demand. If there is a willing mouth to suckle, then the body will continue to produce the milk. During the early days of nursing a new baby, the body will need to adjust to the baby’s requirements. Engorgement is simply the result of the body’s overcompensating and producing an oversupply of milk. Personally, I think that if you can get engorged, that’s a pretty good sign you have more than enough milk for two.