I also have an iPF 8100 as well as an 8300, both getting relatively light use since I'm an individual photographer/printmaker not a print shop. Had no need for the 8300 but got it on one of those Canon USA rebates + free ipad deals from Lexjet that brought the price down to about the replacement cost of the new set of inks which comes with each iPF printer. My 8100 lost a printhead a little after one year, but Canon USA replaced free of charge. The phone support guy said the original heads had been redesigned. They are now identical to the 8300. My 8300 also had a head go bad after about a year and a half. Canon didn't offer a free head on that situation, but next the new replacement head died within one year after that, and Canon does replace any head that goes bad before one year. So, you might want to call Canon and see if your second bad head can be replaced at no charge.
After that incident, I began to pay more attention to my daily/weekly usage. Like you, both my machines are lightly used. Even though I leave them on, I noticed that if left unused for a week or so, they never auto initiate a cleaning cycle when not in use, but they did always initiate a cleaning cycle right as I spooled the first print. This cleaning pattern thus seems to be initiated by a simple timer cycle that keeps track of the time between print jobs, and it causes a huge amount of wasted ink ending up in the maintenance cartridge. So, about three months ago I decided to implement a simple nozzle check every other day on each machine. I just feed each unit a letter size cut sheet of plain paper and instruct each printer to run a nozzle check. The nozzle check exercises all the print channels including both blacks and uses only a negligible amount of ink. And much to my pleasant surprise, every nozzle check has been coming out perfect, so no further cleaning cycle is required and the forced head cleaning cycles at the beginning of actual print job do not occur. I'm saving a huge amount of ink now. I'm keeping my fingers crossed that head life will improve as well. Anyway, even with two head replacements over the past few years and one blown motherboard (replaced under warranty), my overall sense is that although these Canon iPF printers are designed for much heavier use, they are still a relatively trouble-free choice for individual users who don't subject them to heavy usage.
cheers,
Mark
http://www.aardenburg-imaging.com
