You can check the approximate service life of the maintenance box from the control panel. Press the 
button, and then select Printer Status.
To confirm the actual ink remaining, visually check the ink level in the printer's tank.
You can also check the approximate ink level and the approximate service life of the maintenance box from the status monitor on the printer driver.
Windows
Click EPSON Status Monitor 3 on the Maintenance tab.
If EPSON Status Monitor 3 is disabled, click Extended Settings on the Maintenance tab, and then select Enable EPSON Status Monitor 3.
Mac OS
Apple menu > System Preferences > Printers & Scanners (or Print & Scan, Print & Fax) > Epson(XXXX) > Options & Supplies > Utility > Open Printer Utility > EPSON Status Monitor