Is it obligatory to pay Zakat on the full amount saved for two years, or only for the last year, and what is the ruling on repeatedly paying Zakat on the same amount?

"Paying Zakat on money for the past year does not exempt one from paying it for the subsequent year. If money reaches the nisab and a full year (hawl) passes over it, Zakat becomes obligatory. Therefore, you are obligated to pay Zakat on all saved money. If land or an apartment is purchased for personal use (for living in) and not for sale, there is no Zakat due on them."