Breastfeeding questions

mama.jinx • Wife // mama // coffee snob // Gemini
I don't have children yet but I work at a daycare. We measure how much the babies eat from their bottles to the parents know how their days went 
How do you measure how much intake the baby gets when feeding straight from the breast? I have friends who are avoiding bottles and wanting to breastfeed breast to baby's mouth strictly. How do you measure that??
I guess I also want to know because hopefullyyyy we can try for a baby soon given we just bought a house finally ❤️❤️❤️
I didn't want to google things because I didn't know what to put in the search bar lol