The Brother MFC-L3720CDW goes from 1,200-page starters to 3,000-page high-yield on black

The MFC-L3720CDW runs four TN229 cartridges with quite a spread between standard and high-yield. Standard black gives you 1,500 pages and colors just 1,200 — functional but not impressive. The TN229XL series changes the picture: black jumps to 3,000 pages and colors to 2,300 each, effectively doubling your runtime. The separate DR239CL drum is rated for 30,000 pages, so that component will easily outlive several full rounds of toner replacements.