Several months ago I began to have a problem with the right head on my iPF 8300. With two weeks left on the warranty, Canon overnighted a new head to me and I was up and running less than 24 hours after discovering the problem.
I doubted my luck would hold out for the left head and sure enough, it lasted until yesterday, after 11,000 sq. ft. of prints, when faint banding started appearing in solid blacks on matte paper. Several light and one deep head cleaning and a firmware upgrade failed to solve the issue. I reported everything to Canon tech support, read off the the head serial numbers and some error messages I had gotten, and as I suspected, it was time to replace the left head. What didn't expect, three months past the end of my warranty, was the tech support guy's next sentence, "How about I send you a new head as a courtesy? It will go out today and you should have it tomorrow."
Replacement heads cost about $350-400 for this printer, a price I think is well worth it since I never experience any head clogs and related down time and wasted prints like I did on my older non-Canon printers-well, at least until the head dies ;-). All my tech support needs on this and my original 8100 printer have handled promptly and in exemplary fashion. But this experience just sweetens the pot.
Thank you, Canon!