I just put the cartridge in, and works great. I have no idea how long it will last, as this is the first cartridge I have needed since purchasing the machine. I will tell you that all information shows I was suppose to use a 120M cartridge, but after three tries and none worked and tried the 121M and it works great. All other cartridges are 120, so Canon messed up which cartridges can be used in this machine TM-355. The 121 cartridge is quite a bit more money than the 120 one! That was the only frustrating part.