Never. They have their days that hey do, but mine keep on waking in the middle of the night. Depends on each child

All babies are different but mine started sleep through at 4weeks old (1bottle fed 2breastfeed)

I breastfed so my son would wake up alot to feed, think he was about 2 years old when he starting sleeping through the night consistantly

I think it varies a lot. My only daughter started sleeping 10 hours in a row the night before turning 2 months old.