I print mainly black and white documents. How can I stop the life of my color toner cartridges from decreasing when I print?

What is the difference between the toner cartridge and the drum unit?

Can I use non-Brother or third party supplies with the Brother machine?

I still receive the error message "Replace DrumX" or "Drum End SoonX" after I replace the drum unit with a new one.

I just replaced the toner cartridge and the LCD continues to display the message "Toner Life End" or "Replace Toner".

Replace Fuser

Replace PF Kit xx

Replace Belt

Replace WT (waste toner) Box

Replace Toner

What are the expected yields of the consumables?