I recently bought an Epson r3000. I'm very satisfied with what I'm getting out of the printer. I do have one question concerning the ink cartridges. I think the printer requires all cartridge spaces to be occupied in order to function. From what I've read, switching back and forth from the glossy photo black ink to the matte black ink wastes a good bit of both in the process. Since I only use the printer for photographs and I only print on Epson's Premium Glossy Photo Paper or Glossy Exhibition Fiber papers, the ink cartridge filled with matte black ink will never get used in normal printing. Should I occasionally print something using the matte black ink or is it okay to just leave it unused. If I don't use it for printing at all, do I need to replace this cartridge occasionally even though it will never have any ink used out of it?