4 cartridges are packed individually and can be changed at different paces. The interest of their economic grouping 4 is (145 euros instead of 190) .Some complain about the short life of the cartridges. To do this more than expected last cartridges, do not forget to configure your printer in "draft" if necessary, and to settle the options, tabs "graphics" mode "Toner Save" at the bottom by dragging a little to the right cursor ... This works and prints obtained may suffice if it is not about documents requiring high quality ... Furthermore, there are economic as Ecofont fonts whose characters have small holes invisible to the naked eye for usual font sizes, but that allow a saving of 20 to 50% toner ...