Which is better: to perform Hajj every year for one who is able to do so without hardship, or to perform it once every two or three years?

Allah has ordained Hajj once in a lifetime for those who are able, and anything beyond that is supererogatory. Repeating the supererogatory Hajj depends on a person's financial and health status, the condition of their relatives and the poor, the general interests of the Muslim community, and their standing within the community and benefit to it. Each individual should consider their circumstances and prioritize what is most beneficial for themselves and for the Muslim community.