I have been using my HP OfficeJet Pro 6968 color inkjet printer for 8 years now. I have heard and read many reports of Inkjet printers degraded print quality over time. I also understand there is a correlation between using off-brand ink cartridges and degraded print quality. My HP has the same print quality today as when I first put it into service. I swear by Genuine HP Ink Cartridges and credit the longevity of my printer with using only genuine HP Ink.
Having been burned by refills that do not work whose guarantee has expired by the time I use my spare cartridge and then by HP changing their design and firmware to shun last years brand new sealed cartridges I can buy cheaper on ebay I am forced to local full price ink and so I am using smaller carts to preserve any guarantee.