do you mean if there's enough breast milk or if bfing routine is established?
I knew i had enuf breast milk when I was dying from pain from the engorgement... If no milk, won't get engorged. baby is also satisfied after each feed, gaining weight, having enough wet and soiled diapers...
Also, the flow is now better. If i press my breasts, the milk will shoot out! hahaha
As for bfing routine being established, i guess you'll know it when baby gets hungry at regular intervals and you dont't get leaking or painfully full breasts anymore.