Should the owner be compensated for the years of residence in the old-rent apartment, taking into consideration that the money taken in exchange for vacating the apartment equals what was spent on it, and that the original owner has passed away and his heirs are many?

The system of perpetual lease, practiced in some countries, is an unjust system and contrary to Islamic law. The lease is invalid due to the absence of a specified duration for it. Addressing this situation, given the long period and the death of the original owner and tenant, with the heirs of each remaining in their predecessor's position, is a difficult matter and is best suited for judicial resolution. The financial obligation in an invalid lease is the equivalent rent (ujrat al-mithl), because the utilization of benefit through an invalid lease necessitates the guarantee of the equivalent rent. If the paid rent is the equivalent rent, then the tenant is not obligated to pay anything further. However, if the rent is less than the equivalent rent and without the lessor's consent, then the tenant's liability is not discharged except by paying the equivalent rent. The equivalent rent is determined by experts in this field.