Hajj, the annual pilgrimage is held every year and millions of Muslims gather together in Makkah to accomplish this fifth pillar of Islam. Muslims are required to perform Hajj at least once in a lifetime.
Allah says “And [due] to Allah from the people is a pilgrimage to the House - for whoever is able to find thereto a way.” [Quran 3:97]
Prophet Muhammad (pbuh) said, "Performance of Hajj is once and anything more than that is a voluntary act (of worship)."
Therefore, it is quite clear that Hajj is obligatory /compulsory on a Muslim only once in a lifetime if he/she is capable of undertaking this spiritual journey. Hajj is a challenging act of worship that requires huge expenditure and physical exertion. There are no restrictions on performing Hajj more than once but you must realize that there are rules set by authorities regarding the restricted number of pilgrims who could perform Hajj from every country. So anyone who was lucky enough to undertake this spiritual tour once preferably should not repeat. There are other forms of worship and charitable deeds that one could perform to seek Allah’s rewards. They must allow other first-timer pilgrims to perform Hajj.