Many printer cartridges are like puzzle pieces. But HP's just pop in/out with ease. I haven't a clue how long these will last since I just recently bought a new printer after having a Canon for a while. FYI: I used to prefer HP but that is no longer the case. Staples just didn't have the kind of Canon I wanted and I didn't realize how disappointed i'd be in getting an HP again after several years with Canon. Also: don't get tricked into the auto-ship program of HP's if you don't use your printer a lot.