Combination feeding is breastfeeding alongside offering bottles of formula or expressed breastmilk. It’s important to understand how breastmilk is made and supply maintained. If you are giving a bottle of expressed milk or formula once a day and pumping around the same time, you may not suffer a dip in supply. Many mums do this at night. Mum pumps and goes to bed/shower etc, and dad gives the bottle and settles baby so mum gets a rest. Mum then breastfeeds the rest of the time.
Breastmilk contains everything your baby needs (in conjunction with solid food after 6 months) to grow and thrive. When your baby enters toddlerhood, and is moving around a lot more exploring their surroundings (often with their mouths) your breastmilk will make more antibodies to protect them. And these antibodies will be tailor-made for your baby. Breastfed children have lower risks of ear, chest and tummy infections (HSE 2019). It also protects them from becoming overweight or obese (obviously, depending on their diet).