What is the expected life of the drum unit and belt unit?

The drum unit (DR-223CL) has an approximate life of 18,000 pages based on one page per job using A4/Letter single-sided pages. The belt unit (BU-223CL) has an approximate life of 50,000 pages based on two pages per job using A4/Letter single-sided pages. The actual number of pages may be affected by factors including media type and media size.