Hajj is mandatory for anyone who is capable (with respect to health, finances, and safety) once in a lifetime. The basis is the Qur'anic verse that states:
"And [due] to Allah from the people is a pilgrimage to the House - for whoever is able to find thereto a way. But whoever disbelieves [or denies the need for hajj]- then indeed, Allah is free from need of the worlds." (Surah Ali Imran : 97)
Hajj is performed over specific days during a designated Islamic month. However, Umrah can be performed at any time.
Our beloved Holy Prophet Muhammad (ﷺ) had also performed only one Hajj in his lifetime in 629 CE.