Settling of inks is the primary concern. Even if you vigorously shake the inks, you could still have problems, since the pigment particles tend to coagulate. I would try and not buy inks over 2 years out of date. I recently used a 3 year out of date red cart for my HP 3100, and I noticed the color was not right on a diagnostic page and I immediately replaced the cartridge with a new one. No problem.