The replacement frequency of baby bottles is related to the material of the bottle, plastic bottles are replaced once every 3-6 months, while glass bottles can be replaced once a year. Baby bottles made of various materials have a certain shelf life, and using them beyond the shelf life is not good for babies’ health and may cause various diseases. Commonly used glass bottles are safe, non-toxic, easy to clean and disinfect, and can generally be replaced once a year. Plastic bottles are divided into various types, PP bottles are recommended to be replaced every 3 months, while PES and PPSU bottles can be replaced every 6 months. Bottles made of stainless steel generally do not need to be replaced as long as they are cleaned and disinfected properly. In addition, baby nipples are recommended to be replaced every 3-4 weeks. In short, the cleaning and disinfection of bottles is crucial, and incomplete cleaning can lead to diseases such as acute gastroenteritis in infants, which must be taken seriously.