What should I do when a 'Cartridge is low' or 'Cartridge is very low' message appears?

The product will display a warning when the toner cartridge is low or very low, but printing can continue until print quality is no longer acceptable. You can enable or disable the Very Low settings to control product behavior at this threshold, and you should consider having a replacement cartridge available to install when print quality degrades. The supplies status page can also be printed to check the approximate percent life remaining. (Page 64)