My Brother laser printer has told me that my toner is empty three times now for the same cartridge. It eventually refuses to print, but that can be overridden with some undocumented trickery. I have manually overridden it each time, told it that I installed a brand new XL cartridge and it just keeps printing. It just told me, again, that the toner is low - I don't believe it, I'll override it again. It would have forced me to throw out at least 66% of the remaining toner if it didn't have the override.