Leases and rental agreements form the contractual basis of the landlord-tenant relationship. A rental agreement is generally made for a short period of time, typically a month, in which case the agreement is automatically renewed each month. A lease on the other hand, covers a set period of time, usually six months to a year, as long as the tenant pays the rent and complies with other significant terms of the lease. When a lease expires, it is not usually automatically renewed.
Leases and rental agreements should be in writing so that there is a clear understanding between landlord and tenant on all key issues of the tenancy. Oral leases and rental agreements are legal (and enforceable) for month-to-month tenancies and, in most states, for leases of a year or less. While seemingly easy and informal, oral or verbal agreements often lead to disputes as either side may forget key terms as time passes by.
State laws (and the rental documents themselves) typically spell out how and when a landlord or tenant may end a month-to-month rental agreement or a fixed-term lease.