A:Answer Hi Bobg26, Using the Epson T502 refill bottles, the EcoTank ET-2850 is designed for, you can expect an average of 7,500 black pages and 6,000 color pages. You do not need the other colors to print using black, but if one of more colors is expended, we recommend refilling them as soon as possible to avoid having ink dry around the print nozzles. This could potentially cause clogs. Regards, Mark - The Epson Team.