The BC12e is a photo cartridge comprising of 3 individual components - the print head, a photo black ink tank (BCI12PBK) and photo colour ink tank (BCI12PC). Each element has a different life, so when either ink tank is exhausted, it can be replaced without the expense of replacing the whole unit. The photo black lasts approximately 35 pages and the photo colour for approximately 30 pages. You will probably need to replace the whole unit (BC12e) only when you detect deterioration in print quality. This will ensure optimum print quality.