Brother MFC-8820DN - Manual (Page 411)

SPECIFICATIONS S - 7
Consumable items
Toner Cartridge Life
Expectancy TN-530: Standard Toner Cartridge - Up to 3,300*
pages
TN-560: High Yield Toner Cartridge - Up to 6,500*
pages
*(when printing letter size or A4 paper at 5% print
coverage)
Toner life expectancy will vary depending upon the
type of average print job.
Drum Unit Life
Expectancy Up to 20,000 pages/drum unit (DR-500)
There are many factors that determine the actual
drum life, such as temperature, humidity, type of
paper, toner you use and number of pages per print
job.