When your toner is finished, your laser printer will not work correctly.  You will know that your toner cartridge is in need of a change when the following symptoms are present:

- The printer will have its yellow Led light blinking that shows that the toner is low
- The printouts from the printer will have a faded look.
- There could be a print defect on the printouts
- There could be smears or lines on the printouts

When you see the above symptoms; then it is the time to buy a new toner or a replacement toner.  You will need to go through the following steps to change your toner cartridge.

1) First identify the exact model and the make of your printer. 
2) Call your nearest computer shop to ask for the compatible toner for your laser printer.
3) You can buy an OEM Toner cartridge, compatible equivalent toner or refurbished toner cartridge.
4) Take out your old printer toner cartridge by opening your printer cover and by sliding the toner out of your printer.
5) Place your new printer toner in front of you and take out the strip inside the new toner. (This strip will not be found in refurbished or recycled toners.  If you don’t take out this strip, your printer will print blank pages as a result)
6) Gently push your printer toner in to your printer.  It should snap right in to its place.  Never force it inside, as you may break your printer parts by using excessive force.
7) Close your printer cover and restart your printer or reset it.
8) If the toner is installed properly, the ready light will be blinking green.
9) Get a test page printout to make sure that your toner cartridge is installed correctly inside your laser printer