This Australian website gives a good rundown on printer ink shelf life
Ink still packaged
Basically, Original Equipment Manufacturers (OEMs) as well as third party manufacturers can specify anything between 12 months and 24 months to be the life of their ink cartridges. However, they phrase it different. Typically, it’s phrased as the expiry date or install by date.
Ink in use within the printer
This seems to depend on amount of useage and the makeup of the ink. Higher viscosity leads to shorter life when in low use.
The worst thing, however, is that the printer components get damaged as highly viscous ink solidifies in critical areas.
This is a problem that infrequent users especially face. So, what can you do to prevent this from happening?
The first thing to remember is that if you use your printer at least once every week, then you will be increasing the shelf life of printer ink cartridges in your printer. This happens because the ink inside your installed cartridges gets moved.
So, you need to print something which uses every cartridge in the printer at least once a week. If you have nothing to print during the week, then just print a test page. That way you keep the printer components clear of solidified ink.