It is all about how you should sleep and train your baby. A baby will wake up to be fed around 3-4 hours. But as they get older and approach six months they will often be able for long stretches even for some all night. They might wake up crying soon after they have been put to bed Or times during the day.
Babies appear to learn that their cries bring parental attention and might stay awake for the reason ruining both their own sleep and their parents also.
Leaving the baby to cry for a certain period of time. before checking on them or staying with them in the room but not interacting with them.
The method have been researched for decades. Have we learned anything reliable about that work?
As you can see in the image the baby is sleeping without crying or making any noise. As it is depressingly common when it comes to the science of parenting the evidence of sleep training is to be used as a scientific term a complete mess.