I've had very mixed results with these cartridges. The first time I bought a set of black ink and color cartridges... they worked just fine and lasted about as long as the Canon brand (I only print maybe 10-20 pages a week). The second time I bought two sets, the black ink only lasted about a week before I had to change it (same use, 10-20 pages). The replacement worked fine though so I thought maybe it was just one dud, not the norm. I recently bought a fourth set when it was time to change cartridges again. I had the same problem I had the second time around. The black ink cartridge only lasted a week (again, with only 10 prints max). I had to go out and buy a canon cartridge to replace it.At this point, I would say it's not worth it if there are this many duds floating around. They might be cheaper at first, but (at least for me) they only work correctly about half the time which cost me more money to replace.