Well that's the thing. I can't remember exactly either. But it was a gradual process, for BOTH issues you mention.
Got more and more comfortable walking away briefly, putting away clothes, straigtening this or that, getting ready for tomorrow. Still nothing I can't put down and walk back in and engage the kid in the tub, you know?
I want to say maybe 8 or 9? Still I couldn't trust them to wash properly, still can't (tehehe, 18, 16, 13).
Like when my daughter was 5 (youngest) I wouldn't go downstairs where I'd loose the sound of her.
Guess this doesn't help much, only that it's a question of your comfort level. If it makes you too nervous, don't do it. Mom's gut is ALWAYS right!
:)