Quoting Greyson's MilkMaid:" similar to what im talking about: (photo found on google) i dont have one.. didnt plan on buying one for a few months.. just wanted opinions on how early."
I did it. I have a little einsteins jumper. But personally mine was to keep him out of his older siblings. He couldn't touch the floor, and he just leaned forward in it and looked around. I often put things around him or a blanket under him. It was just to give him something to do out of the way. And I never left him longer than 15 minutes in it
Here he is at 2 months 7 days ish. His birthday was December 31 and this was taken March 7th.
But that's just me, I have 2 kids and now this one.