When must the Hawl (lunar year) be calculated for paying Zakat on rented real estate if the rent is received in installments or at different times?

The Hawl (Zakat year) for real estate rent begins from the contract, because the owner becomes entitled to the rent upon the contract, and it is established by it, even if it does not become fixed until the benefit is utilized. So, if the benefit has been utilized, the rent collected, and a Hawl has passed for it from the contract, its Zakat becomes obligatory. However, if it was collected in the middle of the year and spent before the completion of the Hawl, then there is no Zakat due on it.