Well, I waited until my HP 8620 needed three out of the four cartridges and after installing the three the forth one needed it also. I let it process like normal and it made a strange noise and an error message came up concerning one of the cartridges. I opened it bay and removed it and it was leaking badly. I removed them all and cleaned the mess up the best I could with alcohol and paper towels. I bought another HP setup and my printer is working fine. I would not recommend this since this happened to me. I maybe the one in a thousand that it happened to but I thought my review may help anyway.