Different materials of the bottle, the use of time will be different: 1, plastic bottles used for a period of time, the bottle will be scrubbed and high temperature disinfection, there is a fuzzy mist or milk scale accumulation, it is recommended that 4-6 months or so for a change.2, glass bottles, the material itself is highly stable, the internal structure of the stability of the bottle can be replaced in a year or so, but if the bottle cracks should be replaced in order to avoid scratches to the baby. 3, Silicone bottles can be used for a long time because they are resistant to high temperature and aging.4. Stainless steel bottles are chemically stable and not easy to corrode, so they can be used for a long time.