-It is essential (wajib) for every adult Muslim to recite the Takbeeraat of Tashriq after every obligatory (fardh) salah, which is performed with congregation (jamah), from the Fajr of the 9th of Zil Hijjah until after the Asr of the 13th Zil Hijjah

-They should be recited (at least) once in an audible tone. 

-It is desirable for those who perform their salah alone (men or women) and travellers, to recite them.