Epson, at least, uses a formulation that leads to most generic inks causing irreparable clogs. I dunno how they do it, but I've seen it happen in two Epson printers--worked fine for a few months, switch off to a non-Epson ink (of different brands in each case) and within a week the printer doesn't work. No printing, at all, just makes noise and moves its little bastard head around doing nothing. When researching the topic, I found that design professionals (who print a lot, and use the big non-cartridge ink systems) recommend never using Epson inks to start with, and always using the generic brand you plan to use for the life of the printer...which apparently makes this problem go away.

Of course, after five dead inkjet printers (HP, Epson, Lexmark, HP, Epson) I finally got pissed off enough to refuse to buy another one. Ever. I bought a networked Konica Minolta color laser for about $800 six years ago, or so, and it's served me well ever since, and cost less than another five inkjet printers and their outlandish ink prices. I've only had to replace one toner cartridge (black) in that time, and I expect to get another few years out of the printer. It also has Postscript support, so I don't have to think about drivers (which is irrelevant to some folks, but I never want to spend an afternoon fighting with printers again...and a networked Postscript printer is the only way to guarantee that I don't have to).

When my dad started talking about buying a new inkjet after his third HP started banding badly (and new cartridges, and cleaning, didn't fix it) I bought him a $200 laser printer. Best $200 ever. I buy him a new toner cartridge every year for Christmas...it's held up great for three or four years now.