Some are Defective
There is nothing more frustrating than HP cartridges. Sometimes they work and sometimes they don't. In either case, they're expensive and a hassle to return. For example, you have to make sure that the expiration date (which seems to be a gnat's lifetime) hasn't passed. Then, if you have one that hasn't expired, you may get the "BAD PRINTER HEAD" message. There are so many things that go wrong with HP cartridges that I am replacing my HP printer with a different brand. I'm tired of the money I'm spending on the cartridges and the time I've spent making sure that they work.