A certain particular order is very necessary while reciting daily Zoroastrian prayers. The selection of prayers differs according to the different gehs.
Prayers always start with the Kasti ritual followed by the Saorsh Baj. Thereafter any of the five larger gehs are prayed according to the time of prayer.
The prayers that follow the larger gehs are different in the different gehs:
In the first three gehs it is mandatory to recite Khorshed Nyash, Meher Nyash, Doa Vispa Humata, Doa Nam Setayashne and Char dishno namaskar (homage to the 4 directions) in this particular order.
In the fourth geh (Aiwisruthrem) the Sarosh Yasht Vadi and its Nirang is to be recited followed by the Doa Nam Setayashne.
In the fifth geh (Ushahin) the Sarosh Yasht Hadokht and its Nirang is to be recited followed by the Doa Nam Setayashne.
The above prayers are considered the Farajyat (obligatory prayers) for that particular Geh. After that any Naysh or Yasht can be recited in any order, after the end of which a Doa Nam Setayashne needs to be recited.
If Patet Pashemani, Patet Ravan-ni or Satum no kardo has to be recited, it has to be done here. If one is doing ‘Sarosh Patet” for a deceased in the Aiwisruthrem geh, Patet Ravan-ni is to be prayed immediately after Sarosh Yasht Vadi, its Nirang and Doa Nam Setayashne.
If one recites Patet Pashemani or Satum no Kardo, as the penultimate prayer, the Doa Nam Setayasne should be recited before that and not after that.
The daily prayers end with the recitation of Tandarosti. Certain short prayer like the Din no Kalmo, 101 names and Cherag no namaskar (in Aiwisruthrem geh only) can be recited immediately after the Kasti or in end just before the Tandarosti.
In case one wants to recite the Hoshbam prayer at dawn, one has to do the Kasti, Sarosh Baj and Ushahin geh if it is to be recited about an hour prior to sunrise. Kasti, Sarosh Baj and Havan geh has to be recited if the Hoshbam prayer has to be done within about an hour after sunrise.
The time of dawn (Bāmdād/ Hoshbam ) is regarded as the best time for prayer as it is conducive to a meditative, contemplative and reflective state of mind. It the calmest part of the day, when there is very little external disturbance and the benevolent, positive forces of nature are strongest and the currents of spiritual energy are undisturbed.