The most important source of information about the rights and responsibilities of residential landlords and tenants is the written lease agreement. Some landlords prefer oral agreements, but it is more common for them to require the tenant's signature on a written lease—and a written lease protects the tenant more than an oral agreement. Be sure to read the lease carefully before you sign it.

If a tenant wants to change part of the lease, the tenant should discuss it with the landlord. If the landlord agrees, the landlord and tenant should decide how they want to word the change and then write it into the agreement. Both the tenant and the landlord should then initial the change. For example, many standard leases prohibit pets, but the landlord may be willing to accept a pet if the tenant puts down extra money as security (a pet deposit) to protect against any damage the pet might do.

A state’s landlord-tenant laws may provide additional rights and responsibilities and further define the rights and responsibilities identified in the lease agreement. These laws vary from state to state and are usually located in a state’s statutes.

In Colorado, the written lease agreement is indeed a crucial document for both residential landlords and tenants as it outlines their rights and responsibilities. While oral agreements are legally binding in Colorado, they are less common and provide less clarity and protection than written leases. Tenants should read and understand the lease before signing, and any modifications to the lease should be negotiated with the landlord. Once agreed upon, changes should be written into the lease and initialed by both parties to ensure they are legally enforceable. Colorado's landlord-tenant laws, which are found in the state's statutes, supplement the lease agreement by providing additional rights and responsibilities. These laws cover various aspects of the landlord-tenant relationship, such as security deposits, notice periods for ending tenancies, and maintenance obligations, and they cannot be overridden by the lease agreement. It is important for both landlords and tenants to be familiar with these laws to ensure that their lease agreements comply with state regulations and to understand their legal rights and obligations beyond the lease terms.