If your printouts become too light, or you see dark or light bands across them, you may need to clean the print head 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 gaps in your printouts, even after cleaning the print head several times, you can run a Power Cleaning.