The lease or rental agreement is the key document of the tenancy, setting out important issues such as:
Leases and rental agreements should always be in writing, even though most states enforce oral (spoken) agreements for a certain period. While oral agreements may seem easy and informal, they often lead to disputes. If a tenant and landlord later disagree about key agreements, such as whether the tenant can sublet, the end result is all too likely to be a court argument over who said what to whom, when, and in what context. This is particularly a problem with long-term leases, so courts in most states will not enforce oral agreements after the passage of one year.
For information about what to include in a lease or rental agreement, see the article Ten Terms to Include in Your Lease or Rental Agreement.