Epson 1500 - Manual (Page 165)

Consumable products
Imaging cartridge: (S051011)
Storage temperature: 0° to 35°C (32° to 95°F)
Storage humidity: 30 to 85% RH
Life: Typical imaging cartridge life is up to
6000 pages under the following conditions:
Letter- or A4-size paper, continuous
printing, and 5% print ratio.
Example of a 5% print ratio: (Reduced
printout of letter size paper.)
Note:
The number of pages that you can print with an imaging cartridge
varies depending on the type of printing you do. If you print a few
pages at a time or print dense text exceeding 5% print ratio, your
cartridge may print fewer pages.
Technical Specifications A-5