How young is too young to leave a child "alone"?

[Biggie]

I think there is a certain stage when a kid is more "accident prone" depending on your kid's personality and your home environment. Our first was a very cautious boy since a baby so we don't really have to watch him too closely -- but our home had stairs so we needed to make sure he is kept away from stairs. Our second one is more adventurous so we are a bit more cautious, especially for the few weeks when he just learned to walk and he liked to climb or grab all the things that he couldn't reach before. Slowly we taught him how to get off the couch safely, what he can't touch etc and we became more relaxed. Since about 16mth we wouldn't mind leaving him alone for a bit here and there, or when he was playing with his older brother (older by 2 yr)

 

[Gracey]

Hi all, thanks for all your stories and suggestions!
No, we don't keep an eye on her every second. That would be insane, especially since my helper doesn't live in, and I work full time.
Like you ladies, there are many times -- esp. in the mornings before my helper arrives -- that I am making coffee, warming up baby's food, getting dressed, answering the phone, and my kid's just running around.
I just meant when the helper's alone at home and going to the bathroom with the door shut.
When I go, I put baby in her playpen for a few minutes. Sometimes she complains, but usually she just plays by herself.
Recently she's been hurting herself alot. Tried to climb up her stroller and leap off. Tripped over something, cut her lip and bled everywhere.
So, personally, if I'm just around it's fine.
But if I'm in the toilet / shower with the door closed -- and there's nobody else here -- I put her in her playpen for a bit.