If you are introducing a certain type of food to your little gourmet for the first time, wait for 3 days to try another food for the first time. This way, you will be able to recognize the food’s impact on your baby and observe whether your baby liked it or not in the next 3 days. Applying this rule -  especially at start of introducing solids -  is crucial for your baby’s health and for you to take action when necessary.
  
When you follow this rule, you can protect your baby against any unsuitable food. More importantly during this time when your baby is forming his own dietary habit and improving his eating skills, you will be able to prepare a healthier diet that fits your baby's special needs.

It is important to introduce new food with a 3-day break so that your little gourmet gets to know the food, grasps its taste. Don’t forget, it’s a whole new universe for him! Observe and easily distinguish your little gourmet’s likes and dislikes;  help your baby to develop his eating skills by himself. Getting a taste of life is priceless and enchanting. Carpe diem! And let your little gourmet joyfully seize these valuable moments.

When you follow the 3-day rule and watch how your baby reacts to each food, it will be easier for you to group the foods. Thanks to this rule, in the following months, you will have no trouble in deciding which foods to combine and which foods to give exclusively.
  
As said, 3 day waiting rule is crucial until your baby builds his own eating habits. After a certain point, you will be able to recognize your baby’s reactions to certain types of food.
 
This rule will continue to be important between months 6 and months 9-10 and after months 9-10 you may stop following it. If there are any family members with allergy history, you should continue to follow this rule as a precaution until your baby is 12 months old. You should consult your doctor in case of any extraordinary situation that may arise.