Formal Voice Lessons at an early age are not always necessary.
Kids can begin to take lessons if they really want to but prior to age 9 the voice lessons should be taught differently than for older kids and adults.
Lessons for young kids should be kept fun so that they do not lose interest.
Younger kids can work more on their ear-training which will help them to stay in tune.
Kids prior to 9 years old should practice and identify music intervals and scales in their lessons.
The main objective of lessons for young children who do a large amount of singing, whether in a choir or on stage, is to prevent them from straining or harming their voice.
Voice lessons for older kids (age 10+) should focus on vocal technique. Many teachers believe that boys need to go through their voice change before they can focus on technique, so ask your teacher for advice.
Kids should learn breathing technique in addition to proper posture.
Teachers should instruct kids as to the proper way to take care of their voice.
Teachers should help children to understand their own unique vocal qualities and also to find material that suits those qualities.
Musical Theater Kids should begin to build a repertoire...a list of songs that they are prepared to perform. This will help tremendously when it comes time to audition.