Various internal and external influences can cause a piano or grand piano to get out of tune. It might be the quality and condition of the instrument, but also humidity, temperature or wood warping. All these factors can change the tension of individual strings. By having your piano tuned regularly, the strings are realigned to obtain the correct tones. A tuning session consists of tempering, realigning, checking and fine tuning. A piano that is tuned accurately will remain stable for a longer period of time.