Times when usage of Miswaak is Sunnah

1. For the recitation of the Qur'an.
2. For the recitation of Hadith.
3. When the mouth emits an odor.
4. For the learning or teaching of virtues of Islaam.
5. For making Dhikrullah (Remebrance of Allah, meditation).
6. After entering one's home.
7. Before entering any good gathering.
8. When experiencing pangs of hunger and thirst.
9. After the signs of death are evident.
10. At the time of Sehri.
11. Before meals.
12. Before undertaking a journey.
13. On returning from a journey.
14. Before sleeping.
15. Upon awakening.

Benefits of Miswak

1. Miswaak strengthens the gums and prevents tooth decay.
2. Miswaak assists in eliminating toothaches and prevents further increase of decay which has already set in.
3. Miswaak creates a fragrance in the mouth.
4. Miswaak is a cure for illness.
5. Miswaak eliminates bad odors and improves the sense of taste.
6. Miswaak sharpens the memory.
7. Miswaak is a cure for headaches.
8. Miswaak creates lustre (noor) on the face of the one who continually uses it.
9. Miswaak causes the teeth to glow.
10. Miswaak strengthens the eyesight.
11. Miswaak assists in digestion.
12. Miswaak clears the voice.
13. The greatest benefit of using miswaak is gaining the pleasure of Allah.
14. The reward of Salaah (Prayers) is multiplied 70 times if Miswaak was used before it.

Using miswak was the sunnah of the Prophet Muhammad (S) as well as of the other prophets.

Abu Ayyub (R) narrates that Rasulullah (Sallallahu Alayhi Wasallam) said:
'Four things are amongst the practices of the Ambiyaa —circumcision, application of perfume, Miswaak and marriage'."
(AHMAD AND TIRMIZI)

Abu Hurairah (R) narrates that Rasulullah (Sallallahu Alayhi Wasallam) said: 'Was it not for my fear of imposing a difficulty on my Ummah I would have ordered that the Miswaak be used for every Salaat'."
(BUKHARI)