Shortchanged. 660 pages/cartridge?  Try 88!
925633
Do you keep track of how many pages you get per cartridge?  It's easy to.

I got ~88 typical pages per normal genuine 02 black - printing white pages with normal black text; never pages that I'd expect would use much more ink.large/solid areas of black. (Our Photosmart C6100 series printer tracks how many pages are printed, so it's not hard to calculate, if one just checks the page count when one changes a cartridge.) (264 pages printed using 3 normal 02 black cartridges over 3 months, total.)
Continuous printing saves ink, sure, but unless there's something defective or dishonest going on, it seems ~87% of the ink in a cartridge was not used to print (but was, rather, spent keeping the printing system healthy while it was in the printer for only a month).  So saying this cartridge will print anything close to 660 pages seems dishonest to me, unless my experience is abnormal.

I'm going to contact HP to see how they handle a warranty request.
UPDATE: NO, I think I'll learn from R. Siegfried's experience (see his review of the regular black twin pack - C9500FN140 at[...] and give up on that idea - doesn't seem worth the trouble. Contacting Amazon seems to make more sense - at least if that's who you bought from.

I was looking for a comparison -HP 02 vs 02XL and found a vendor's wordpress site with some interesting (but unverified) info.
It said that the genuine HP 02XL cartridges have 15ml of ink, while the genuine HP02 Black cartridges have 10ml of ink, and this vendor's compatible cartridges had 30ml of ink.
Whether this translates to more pages or not is an open question (I wouldn't be surprised if the printer insists the cartridge is out of ink long before it is out of ink.) I guess one could weigh the cartridges before and after...

The specs for the HP cartridges from HP say that the 02 and 02XL blacks SHOULD print ~660 and ~1000 typical pages.  How does an HP printer/cartridge determine it's out of ink?  I'd love to know!
3276087
I'm so disappointed.... This ink cartridge MAYBE at MOST printed 20 pages.  I find it hard to believe that this is a true HP product, if so, they need to step their game up - That's terrible!
1097345
My black ink ran out in less than 100 pages on a C4480.

I would recommend buying the extended volume version to increase lifespan.
4055362
I will buy from you again, but for some unknown reason, the blk cartridge decided to over flow the ink on several pages, therefore, wasting quit a bit of the ink.
2184449
My printer did not accept this cartridge.  It was sent along with the multi colored ink pack that is numbered 220.  This is 200 and it doesn't work.  I have wasted about 13.00 now.  Make sure you order the correct ink number.
1530865
reads as unsupported cartridge but it works fine
3991333
Installed OK.  Printed just 2 pages when Error 1203 appeared on my printer.  Check this problem on the internet, found out the cartridge was defective.  After hours trying to overcome this problem I gave up and bought a new printer.  (not a DELL)
1740487
I AM SORRY!
I wrote a bad review.
You did send the correct cartridges.
My best but still weak excuse is we have about 10 printers.
Sorry,
Bob
248821
only 100 pages in but it seems to be working fine.  2280dw

Update - 1700 pages and the left side went out and the right side was still working, contacted them and without questions they replaced it free of charge.  I did not ask for a replacement, fantastic support backing this product.

Carl
1437877
Assuming that the regular toner (not high-efficiency) was included with this printer, I should have gotten 1200 pages out of this thing, but I got 400 (200 double-sided pages).  Very disappointing because I really needed to print a lot for school.  I don't even think I can return it because it's not new, but I need a printer so I can't really return it anyway.  So, I'll have to wait until I can afford the $50 "high-efficiency toner" and hope that I get 500+ pages out of it.  Kind of feel scammed.  :(
2245291
This is my 2nd cartridge in less than a month and it is already fading after 200-300 copies. I wasn't counting copies on the first one because I was too busy running my classroom affairs,  but suspected it was way too soon to start fading and completely faded to non legible copy.
364551
SUPER SHORT LIFE!  LESS THAN 100 PRINTS AND ON REGULAR PAPER WITH DRAFT QUALITY, AND IT IS OUT!!!!
1055294
I own an nx420. If cartridges 124 & 245 are standard & moderate capacity, wouldn't one thin 126 being high capacity would be made for my printer?  Oh, nooooooo. This cartridge is not recognized by my printer. So as I HAVE to get printing done TODAY, I'll have to out into the world and get one. I love technology. I HATE technology!
4707511
I purchase these regularly, but haven't been printing as much lately. I installed this cartridge days ago, and have printed maybe 1000 sheets, and it seems to be out of ink already. I usually get many more pages. Since things have been slower I had not yet ordered a backup unit, so may have to go to a box store for a purchase in the next couple of days.
1669158
Purchased this awhile ago so leaving a review after it ran out of toner.  Based on the printer stats this cartridge printed 2,413 pages at 5.64% coverage and there was 10% of the toner remaining.  I changed cartridges due to incomplete printing (streaking) so could not use the last 10%.  I would call this a successfully replacement cartridge purchase, however, extrapolating page count for the remaining 10% of toner and accounting for the 0.6% more coverage than advertised, this would still fall just slightly short of the claimed 3k pages @ 5% coverage.  Print quality on the first 2.4k pages was just fine.  I did not repurchase yet as I am doing the same evaluation on two other competitive cartridges.
752501
Cartridge not compatible - total waste of time and dollars.
4295198
This is a great printer until suddenly decides to consider full cartridges as empty and flipping their plastic indicator to empty after printing two pages.  I tried three new cartridges that I had.  Then took it to a printer service place, it flipped their full cartridge indicator as well.  The Cartridge supplier says this is a known problem and that they have customers come back thinking the problem is with the cartridge when the problem is with the printer software or some "chip".  My service person bypassed the sensing switch with no success.  It is what it is.  What a shame.