Pacifiers need to be replaced frequently, usually in 2-3 months. If there is a breakage or gum loss during use, it should also be replaced in a timely manner. A. How to determine whether the nipple is suitable When replacing the nipple, pay attention to the purchase of a nipple that is in line with the size of the bottle mouth. (2) M type: medium flow, more milk flow, suitable for babies between 3-6 months; (3) L type: large flow, more milk flow, suitable for babies between 6-12 months; (4) ten type: the sign of the cross hole, the most milk flow, suitable for babies over 1 year old. 3, according to the milk flow rate: (1) appropriate: the bottle will be inverted to observe, if the milk flows out drop by drop, and about two drops a second, it means that the pacifier is more appropriate; (2) too large: the milk is not a drop but has converged into a flow, suggesting that the suction hole is too large; (3) too small: baby sucking hard on the pacifier when drinking milk, there are symptoms of bloating and indigestion, indicating that the pacifier is not appropriate. Second, the dangers of unsuitable pacifiers If the pacifier is unsuitable, it can lead to the displacement of the milk teeth and the bottle mouth. Because of the baby’s long-term incorrect sucking posture, the upper row of milk teeth will remain forward due to inertia, pushing the lower milk teeth to the back and causing the milk teeth to shift; and the bottle mouth refers to the baby’s over-turned lips due to incorrect sucking habits. To avoid adverse effects when using pacifiers, parents should pay attention to the following aspects: 1. pay attention to the need for strict disinfection of the pacifier before each use; 2. pay attention to the ventilation holes and pacifier suction holes towards the top during the use of the pacifier; 3. choose pacifiers with anti-collapse design; 4. replace the pacifier in a timely manner according to the baby’s needs. In general, the replacement frequency of pacifiers is 2-3 months, but there are differences in the replacement cycles of pacifiers made of different materials. Pacifiers made of silicone have a slightly longer life span, usually with a replacement cycle of 3 months; those made of latex are recommended to be replaced every 2 months; those made of rubber have the shortest shelf life and are prone to aging, with a replacement frequency of 4-5 weeks. V. How to sterilize pacifiers In addition to regular replacement of pacifiers, the daily sterilization of pacifiers is particularly important, the sterilization methods are as follows: 1, boiling water sterilization: put the pacifier into the water to cook, the time must not be too long, 2-3 minutes can be; 2, steam sterilization: place the pacifier in the temperature between 95-97 degrees Celsius water steam, steam for about a quarter of an hour can be.