A baby that young should be fed on demand, especially when being breastfed. The milk is so perfectly designed that it is digested very quickly and efficiently. Both of my 3. 5 month olds could wait no longer than 2. 5-3 hours between feedings, and those were complete feedings.
A 3 1/2 month old baby should be breast-fed as often as he/she needs to be nourished. By 3 1/2 months old, a baby usually nurses every 4-5 hours. But a smaller baby may need to nurse more frequently. Continue to breast-feed as often as needed to maintain a good milk flow.
Breast feed every three hours. Put the baby on the first breast for fifteen minutes then burp. Put baby on the next breast for fifteen minutes and then burp.
This can vary from baby to baby, but will typically be every 2-3 hours. A baby who is sleeping through the night may need to eat more often during the day, while a baby who is still waking up at night to nurse may not need to eat as often.
My baby is 4 months old.... he nurses every 3-4 hours on demand.... it depends on how much he sleeps at night. If he sleeps 6-8 hours during the night, he is often more hungry.... your baby will let you know when he is hungry....