When to switch nipple size is crucial to ensure a comfortable and efficient breastfeeding experience. Signs indicating a need for a larger nipple size include difficulty latching, nipple pain, excessive gas in the infant, and a poor milk transfer. Conversely, a smaller nipple size may be necessary if the infant exhibits signs of nipple confusion or choking. Monitoring the infant’s growth and feeding patterns, consulting with healthcare providers, and relying on lactation consultants can provide valuable guidance on determining the optimal nipple size for an infant’s specific needs.