Knowledge of state law is crucial to both landlords and tenants. Landlords want to run a profitable business and protect their investment. Tenants want to be happy in their rental homes and protect their rights. And both landlords and tenants want to avoid legal hassles when it comes to rent, deposits, repairs, and other key issues. The bottom line is that a successful landlord-tenant relationship depends heavily on both landlords and tenants knowing and complying with dozens of state laws.