I haven't replaced any up to this point. I've given the s820's and
i950 to both of my daughters. The s820's don't get the usage they
formerly had, but they are still running ok and the i950 still does a
lot of photos. My iP4000 does most of the work now. I still have an
old BJC-3000 that I'm tempted to fire up again just to see if it's
still alive. I've also got a new iP1500 that came as a freebie with a
computer purchase a few weeks ago. If I can ever get my office
cleaned up and a little room for another printer, I'll see what it
can do. As to the 18 month longevity of the print head, there have
been several threads in the past discussing the limited lifespan of
Canon print heads. The discussions centered around the fact that it
didn't seem to matter how much printing or what ink was used (OEM or
3rd party), they all seemed to fail after a certain period of time.
Check out a thread on
www.nifty-stuff.com It describes what you are
referring to and the cause. The OP even went so far as to disassemble
a print head and (I think) reassembled it and it worked ok.
Ron