You can check the approximate service life of the maintenance box from the printer's control panel. Select 
on the home screen.
To confirm the actual ink remaining, visually check the ink levels in all of the printer's tanks.
Prolonged use of the printer when the ink level is below the lower line could damage the printer.
You can also check the approximate ink levels and the approximate service life of the maintenance box from the status monitor on the printer driver. See the related information link below for details.