Our grandchildren's pediatricians always say what "percentile" they are in weight, length, head circumference. how important is this info?

Important:to a point: Growth percentiles are monitored to ensure the child child's interval growth in different areas is appropriate. If the child goes from being in the 90% to the 20% in a short period of time, it could be of concern. Also, if percentiles for different growth parameters are way far apart, it could indicate the child is underweight, overweight, etc. Most important is to follow these over time.

Screening test: Most adults get used to screening lab to "check out the system" as part of a visit.For kids, we have growth and physical development that provides us with the same kind of information.I can anticipate where on a growth chart a kid should be from the size of their parents. Then, as long as the kid stays within expected percentiles for growth and development, I have good evidence for good health.