Generally, wood used for woodworks are used after drying for 5 years because of it's nature to equalize it's moisture to the surrounding environment. If the wood contains high moisture it will expand and will likely to change shape. Depending on the climate or weather, wood changes it's weight as if it's breathing. Saburouemon's chopsticks are dried enough naturally and chemically and are unlikely to get influenced by the temprature nor humidity but please handle them with care.