The cost of the ink is insignificant when compared to the cost of paper and press time to reprint a job. Sheetfed inks have a shelf life of about one year. After a year the driers in the ink can become less effective, leading to increased drying times, offsetting, more rub, and marking problems. Old ink can be especially problematic when printing on stocks such as cast coated papers, matte, and dull stocks. When ink is received, it may have a manufacturing date on the can. If not, write the date you received the ink on the can with a permanent marker. Write on the can, not on the lid. Rotate you ink stock; use the older ink first. UV inks have a shelf life of about six months. Using old ink can be false economy.