Is zakat due on savings every year, or once, given that the nisab has been reached and the only source of income is salary?

Zakat is obligatory on saved money if it reaches the nisab (threshold) and a full lunar year (hawl) has passed over it. It must be disbursed at the completion of each lunar year, and disbursing it only once is not sufficient. The amount of zakat is one-fourth of one-tenth (2.5%), and it is to be given to the deserving categories mentioned in the verse regarding zakat beneficiaries in Surat At-Tawbah. As for what is earned from salary, there is no zakat on it if it is spent before the completion of a full year.