How do you know when you should replace the ink cartridges?

• Epson's Status Monitor 3 will indicate on your screen, that ink levels are low or you're out of ink. Make sure you only remove the yellow tape seal from the top of any ink cartridge you install into the printer. Also if your in cartridge has been in your printer longer than 6 months it may need replacement. Caution: If the blue label has been removed from the ink cartridge, the cartridge will not function correctly and it needs to be replaced. More importantly, to avoid potential damage to the printer, do not install the cartridge if the blue label has been removed.