Depends on what u want to do with the milk. If u are not freezing the milk and not building a stash, then milk bottles. Otherwise it would be like what the lady above mentioned. I dun have a lot and I never build stash (I am temp a SAHM), so I just put in bottles, if run out of bottles Caz forgot to give bm, then will use milk bag - but there is the washing and sterilizing which is not that bad because u can do it when u are washing the milk bottle anyway