What are the requirements for the duration stipulated in a lease for a fixed period?

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When the lease is for a duration, that duration must be specified and known, such as one month or one year, with no known dispute on this matter. This is because the duration serves as the determinant and identifier of the contracted object, thus requiring knowledge, like the measure when selling by measure. If the duration is stipulated as an unqualified year, it defaults to the lunar year ('Sanat al-Ahillah') because it is the customary standard in Sharia, supported by Allah's statement: {They ask you about the new moons. Say, 'They are markers of time for the people and for the Hajj'} (Quran 2:189). If a lunar year is stipulated, it is merely an emphasis. If a numerical year or a year by days is stipulated, it equals three hundred and sixty days, as a counted month is thirty days.