Here are a few easy ways you can monitor the life of your toner cartridge so you can anticipate when it is time for a replacement:

1- All printers keep track of the approximate remaining toner levels either on the printer display or via the printer software that is installed on your computer.  
2- Consult your printer manual to determine how to access toner level tracking for your specific machine.  The printer should also automatically generate a message on the display or your computer when it is time to replace a cartridge.  With most machines, you do not need to replace the toner cartridge immediately when this message first appears.
3- If print quality starts to get spotty, remove the cartridge and gently rock it back and forth a few times over a trashcan to redistribute the toner powder and then reinstall into your printer.  This process should keep the cartridge running a bit longer, and hopefully get through a few more print jobs.

However, if you are looking for Sharp copier toners, you can visit our website i.e. House of Toner and you will not regret it. We offer Original, Compatible and Re-manufactured copier toners at a very reasonable prices.