Another alternative is to take printer with you and use buttons on front panel to manually do a cleaning every so often.

If you can locate some cleaning cartridges on net, just install them and run a few head cleanings, leave cleaning cartridges in printer then turn it off and enjoy your trip. The cleaning fluid will keep your print heads moist and ready to print when you get back. Tape up your ink cartridges and store them in an upright position, i.e., normal position they would be in if they were in your printer.

While Roy's 3 month leave is probably exception rather than norm it still raises question of what to do in his situation. He decided to do nothing and hope for best which was probably best choice.

The ink which flows through each nozzle assembly functions as a lubricant and coolant for nozzle: if there is no ink in chamber when resistor turns up heat, nozzle assembly will quickly warp and break apart -- resistor can reach a temperature of hundreds of degrees very quickly! If print head is allowed to begin this process of burnout (i.e. if ink cartridge is not refilled or replaced promptly), damage may range from poor print quality (streaks or lines across page, bad coloration, light or dark patches on page) to serious damage to printer.

It is very important never to attempt to print with an empty ink cartridge. If in doubt, top off your cartridges frequently (the leftover ink from your inkjet refill kit can be stored until next time you top off).