Boobs come in all shapes and sizes - no pair are the same and they are very rarely a matching pair! During puberty, your breasts will grow and develop. You may notice that at different points in your menstrual cycle, your breasts feel more tender or may even change shape or size. You will come to recognise what is normal for you. Checking your breasts regularly by both look and touch is an important habit to get into and these links show you how and why.