How long does a ceramic coating last once the bottle is opened?

Once opened, many coatings begin reacting with moisture in the air, so their usable life can be much shorter than the unopened shelf life. Signs that a coating has degraded include thickening, cloudiness, crystals or particles, or unusual flashing behavior. Close the bottle tightly immediately after use, store it as the manufacturer directs and avoid pouring unused product back into the bottle. Check the manufacturer's guidance on shelf life after opening.