This is a tricky question.  There is no perfect age for a child to begin learning the piano.  Generally, I tell parents that if their child:

•  seems interested in the piano
•  understands the alphabet
•  is learning to read words
•  can sit relatively still for fifteen to twenty minutes
•  has enough motor skill to press the keys and keep their fingers curved

then they are probably ready.  The younger the child is, the more the parent needs to be prepared to help everyday and read instructions to them. 

*Here are a few links leading to articles that may also help you decide if your child is ready for piano lessons.

Is my child ready for lessons?

How do I know my child is ready to start piano lessons?

Piano Lesson FAQ's

Most students like to be able to earn something for all their hard work of practicing and passing off pieces.  My incentive program for my students works like this:

Each student will be able to earn points in various ways, and after reaching 25 points, will be able to choose something from my piano store.  I keep an index card for each student and record their points earned on the card.

Instead of focusing on practice time, I plan on awarding points for passing off pieces.  One page passed off equals one point.  This way, students won't be trying to log in certain amounts of time, but hopefully trying to practice in a way that allows them to pass of their music.

I will also award points for extras such as:

• memorizing pieces
• writing in rhythms
• successfully learning a new music concept
• having an exemplary good attitude
• accomplishing a goal
• music theory

I hope this will help my students find more rewards in studying the piano than just showing up for lessons and practicing each week.