We leave our babies as early as 2 mo with grandparents depending on baby dd4 was six months before only because she was still up every two hours.
We have 5 kids and every single.one is as comfortable at grandmas as here. My 2 year old will pack her lovies and ask to go stay about once a week. She loves it over there. My teens stay several weeks a summer with family. my older dds nanny for different family members out of state every summer. They both started at about 14 .