For healthy, term infants, many parents use the 'fridge method' where pump parts are kept in a sealed bag in the refrigerator between sessions to reduce the need for constant washing. However, if your baby is under 3–4 months old or is not a healthy, full-term infant, it is recommended to sterilize pump parts after every use. In warmer, humid climates, be extra diligent about hygiene to prevent bacterial growth regardless of the method you choose.