Breast milk

How do u store your breast milk? I mean , do u all pour in and store between 150ml - 200 ml per packet or according to your baby’s intake? Eg , my baby now drink 90 ml per feed, should I pack them into 90 ml per packet? As I am returning to work in Two months time, I don’t have an idea how much his intake will be. How do I gauge? Is it ok if I pass the infant care few packet of milk (each around 180ml) then they disseminate from there into individual feeding?