Is zakat due on money saved for marriage expenses as soon as it reaches the nisab, or upon the completion of a hawl (lunar year) on it, and what is the ruling on zakat for money paid as a down payment for marriage preparations?

What the sister who asked the question did by giving out zakat on the marriage dowry is correct, because she owned it from the day of the contract, and a year has passed since she owned it. The dowry becomes the woman's property upon the contract, and its zakat becomes due after she receives it and a year has passed, even if it was before consummation.

As for the money that has been saved, if it is not a profit from the dowry, then each newly acquired wealth has its own annual cycle (hawl), and its zakat may be paid in advance along with the zakat of the dowry. However, if it is a profit from the dowry, then its annual cycle is tied to its origin.

The amounts paid for purchasing furnishings before the completion of the annual cycle are not subject to zakat. The goods that were purchased for furnishings are also not subject to zakat because they are goods for personal use. As for the remaining money after paying the installments, it is subject to zakat if it reaches the nisab (minimum threshold) and a year has passed, bearing in mind to deduct the debt from the money subject to zakat if the owner does not have other money to cover the debt. If the furnishings have not yet been purchased, then the amount allocated for them is not considered a debt, and the entire money is subject to zakat if a year has passed and it reaches the nisab.