The Pediatrician Answers:
Growth is greatest in babies, declines during childhood, and then briefly increases again during teenage years. It is often a good indicator of how healthy overall your child is, and at a well child visit, measuring height and weight can be just as important as taking a temperature or examining an ear. Most pediatricians will plot your child's height and weight on a growth chart. "Growth spurts" are usually noted simply by realizing that your child is outgrowing his or her clothes.
Occasional increases in appetite are commonly seen during the first year of life. For instance, you may find that your 9-month-old baby wants to nurse or eat every 3-4 hours than his or her usual 6-8 hours for a few weeks, and this may be perfectly natural.
Another good indicator of growth in pre-teens and teenagers, especially if you don't have ready access to a tape measure, is a change in shoe size. Foot growth often parallels height growth.