Occasions when the Miswaak should be used

 1. Upon awakening.

 It should be borne in mind that the use of the miswaak upon awakening is a separate sunnah and using the miswaak at the time of wudhu is a separate sunnah. 
Hence, if one does not intend making wudhu to perform salaah upon awakening from one’s sleep (or a woman is in menses), then one should use the miswaak upon awakening. However, if one makes wudhu immediately upon awakening and uses the miswaak during this wudhu, then using the miswaak during the wudhu will suffice on behalf of both sunnats.
2. When entering the home.
3. Before reciting the Quraan Majeed.
4. At the time of wudhu.
5. When the teeth become discoloured or a bad odour emanates from the mouth.
6. Before and after eating.
7. When one perceives the pangs of death (sakaraatul maut).
8. If one had made wudhu earlier and the time of salaah approaches, then it is mustahab for one to use the miswaak for salaah to remove any odour from the mouth. Similarly, it is mustahab to make miswaak when joining a gathering.
9. When making tayammum due to illness, or water not being available or being insufficient, one should cleanse one’s mouth with miswaak and perform salaah.