Because print head cleaning uses ink from all cartridges, clean the print head only if quality declines; for example, if the printouts are blurry or the color is incorrect or missing.
Use the Nozzle Check utility first to confirm that the print head needs to be cleaned. This saves ink.
When ink is low you may not be able to clean the print head. When ink is expended you cannot clean the print head. Replace the appropriate ink cartridge first.