If your printouts become too light, or you see dark or light bands across them, you may need to clean the printhead nozzles. Cleaning uses ink, so clean the nozzles only if print quality declines.
You can check for clogged nozzles before you clean them so you don’t clean them unnecessarily.
If you still see white or dark lines or missing nozzles in your printouts, even after cleaning the printhead several times, you can run a Power Cleaning.