Answer: This depends on the age and developmental stage of your baby. Very young babies, eg under three months need their parents close to help them soothe and calm, babies from three to six months shouldn’t be left to cry either, but after six months it can be reasonable to allow them to have short periods of grizzling, but it really depends on why the baby is crying in the first place.
It’s not so much about the length of time they are left to cry but why they’re crying, how they’re crying and the pitch and intensity of their cry. A low level whinge in a baby who’s overtired and is almost asleep is one thing, a high pitched scream from a baby who is hungry and needs comforting is another.
Without giving me more information that’s about as much detail as I can go into. Remember, crying is not about the timing but the reasons why and the individual baby’s age.
Cheers
Jane