Excessive dryness is even more serious as it can cause wooden and felt components to shrink, and , in extreme cases, joints may even come apart. Should you feel that your piano is in an unsuitable environment you should consider using either a humidifier or dehumidifier- your piano technician will be able to advise you. Be sure to close the fall each time after playing. Pianos are delicate instruments which need professional attention periodically. Tuning is the correction of the pitch of each note by re-tightening the strings which tend to gradually stretch.
Regulation is the adjustment of the entire piano action, keyboard and pedal movements.
The stability of its environment and the amount of use a piano gets will very much determine how often it needs to be tuned and regulated. Twice a year for tuning is a good rule of thumb for a piano in a domestic situation. However, your dealer can advise you both about this and about regulation.