How soon do you let your child to wash her hands by herself?
I think from about age 3, I placed a stool by the sink to let my girl stand to wash her own hand. Even though most of the time she does not get them clean properly, I still think it is a good training to let her be independent especially on cleaning herself. Initially she loves to stand by there, spending quite sometime to play with the running water, and especially the soap!
And now, she wants to shower by herself...imagine how much our water bill increased over the last month, Arrgghh!!!!