I was left with my grandparents for 6 weeks when I was about 18 months old. They were people I knew well and saw often. I don't know how I responded. They have both died now and I imagine that they would have glossed over any trauma when talking to my parents. I do know that I cried at the airport when my grandparents left after delivering me back to my parents. I was left with the GPs while my parents drove 3000km to set up our new home/business in an isolated wilderness area. We lived in two tents for the first 6 months.
I doubt it is a choice I would make but DH and I do not have the same pioneering spirit my parents do. And they created a wonderful life for us and are now reaping the benefits themselves having self-funded their retirement at 46 & 50 years old.