Ink has a warranty period, usually 2 to 3 years. If left for too long, some substances will precipitate out, commonly known as colloid failure, so this ink is of little use. Writing and drawing with expired ink will be smudged, which will affect the calligraphy effect. So calligraphers generally don't store ink, but collect Mo Ding. Mo Ding is characterized by stability, which can last for decades or even longer. However, the ink quality of Yidege is good, and the ink that has not been opened for more than ten years is still very good. Some brand inks with good quality have a longer storage life.