All of those things have to be checked immediately every time they cry. The Ferber method, mentioned elsewhere in the thread, says to not even check on the baby

All of those things have to be checked immediately every time they cry. The Ferber method, mentioned elsewhere in the thread, says to not even check on the baby for longer and longer periods after they start crying. During the daytime, if they start crying and you haven't solved the issue, you don't just start ignoring them. Why would you do so at night?