While building I go to great lengths to keeping the workshop’s relative humidity (RH) between 40-45%.
I’ts of great importance that RH is controlled even after the guitar is delivered. When the air is dry or moist the wood swells or shrinks. Wood will always try to equalize to it’s surrounding air and this is what causes wood cracks, finish cracks, high/low action, fret buzzing and lifting etc.. The winter months are always the worst when the air is dry. During the dry season it’s always best to keep the guitar stored in it’s case with a high quality guitar humidifier.