Any piercing comes with a risk of infection, so be prepared for that. It's pretty hard for little children to stay away from fiddling with pierced ears.
Not saying it's wrong to let her have it done - it's totally up to you and I do think a six year old is probably old enough to understand that it will hurt and may be sore for quite some time afterwards - but just don't assume it will necessarily be plain sailing. My nieces both had theirs done when they were about eight - one had no issues at all and the other had loads of problems with hers, despite them both looking after them in exactly the same way.
Really? i think that encourages infection.. Cleaning and touching them everyday.
My lo and my niece did the same thing- none of these special washes/salt water.
Just a couple of twists every couple of days in the bath.
No infection/pain or issues.
There is a reason why every professional piercer (and I don't mean piercers in places like Claire's Accessories, I mean proper body piercers) tells you to keep piercings clean with salt water etc, and that reason is because it's the best thing to do.
Bathwater doesn't kill germs, particularly at the temperature a child bathes in. Any water that a child is sitting in is frankly not something you should be using to clean what is essentially a wound.
You're lucky if you haven't had any infection from zero aftercare, but it's terrible to advise other people to do what you did. Just because you were lucky to get away with it, it doesn't mean other people's kids will be.