The best way to keep your piano healthy is to tune it at least once per year. With the passage of seasons, temperatures and humidity levels fluctuate which cause wood, iron, and steel to expand and contract at different rates. These subtle changes can loosen piano strings and lead to a noticeably flat and inconsistent pitch in less than a year's time. Professional and serious musicians often tune their instruments more frequently to stay in tune with their fellow musicians and to train their own ears to hear pitch correctly. If this is you, consider tuning your piano once per season (i.e. quarterly), especially before group sessions and/or public performances.