I want to know how many time is hajj fardh (obligatory) on a man? If it is once in a lifetime, so how would the other hajj be regarded as for the same person?
All Praise to Allah Subhan o Taala and blessings on Prophet Muhammad peace be upon him His Family and Companions
“..And Hajj (pilgrimage to Makkah) to the House (Ka‘bah) is a duty that mankind owes to Allaah, those who can afford the expenses (for one’s conveyance, provision and residence)...”
(Aal Imraan 3:97)
Hajj is obligatory once in a life for a Muslim who is financially and physically able to perform.But one can perform Multiple or Voluntary Hajj for gaining more more rewards and it would be considered as supererogatory (a voluntary act) for him like voluntary prayers or voluntary fasts to please Allah Swt and to get more closeness to him.We could see in these narrations that
Ibn 'Abbas (RAA) narratedThat the Messenger of Allah (ﷺ) once addressed and said, “O People! Hajj has been prescribed for you." Al-Aqra’ bin Habis stood up and asked, ‘O Prophet of Allah! Are we to perform Hajj every year?” The Messenger of Allah (ﷺ) said: “Had I said ‘yes’, it would have become a (yearly) obligation. Hajj is obligatory only once in one’s lifetime. Whatever one does over and above this is supererogatory (a voluntary act) for him." Related by the five Imams except for at-Tirmidhi.
It was narrated from Ibn ‘Abbas that Aqra’ bin Habis asked the Prophet (ﷺ): “O Messenger of Allah, is Hajj (required) every year, or just once” He said: “Rather it is just once. And whoever can perform Hajj voluntarily, let him do so.”(Sunan ibn Majah)
There is one more Narration which shows that one can perform hajj on behalf of their parents too.
Narrated Ibn `Abbas: A woman from the tribe of Juhaina came to the Prophet (ﷺ) and said, "My mother had vowed to perform Hajj but she died before performing it. May I perform Hajj on my mother's behalf?" The Prophet (ﷺ) replied, "Perform Hajj on her behalf. Had there been a debt on your mother, would you have paid it or not? So, pay Allah's debt as He has more right to be paid."(Sahih Bukhari)
And Allah Swt and his Messenger knows best.