Demand feeding is, I will feed you whenever you're hungry. But you can do a very easy happy medium. You have a schedule, but if the baby gets hungry earlier, then you can feed her. Usually, by around six weeks, they can start sleeping at longer stretches, perhaps five, six, seven hours. Physiologically, by about three months, babies are able to sleep through the night.
Some people say sleeping through the night is midnight to five o'clock.
To me, that's not sleeping through the night. I mean a longer stretch like seven, eight, nine hours. Well it seems that it takes awhile for a newborn baby to be able to consolidate sleep so that they can sleep for longer stretches and have the nutrition in them during other hours so that they can go that long without a feeding. And the key to it is two things. First, figuring out the signs that your baby is tired.