A residential rental contract is a contract specifically designed to rent a residential property, such as a house or apartment. A standard residential rental contract, also called a lease, is usually signed for a period of six months to a year, with a possible option to renew the lease upon expiration. In some cases, a residential rental contract may be a month to month contract; in this case, the contract automatically renews each month until either the tenant decides to move or the landlord decides to cease renting to the tenant. An upfront payment of the first and last month's rent is sometimes required before signing a residential rental contract, as well as a security deposit. The security deposit is held by the landlord until the tenant leaves, and the money is then used to pay for any cleaning or repairs needed. Any unused portion of the security deposit is then refunded to the tenant within a specified amount of time.