Many of the clients with PML of Longmont find it important to have specifics set out. You may want to have a lawyer review the lease.
With rents headed higher and vacancy rates in the single digits, people are doubling up. This can present problems for owners if additional people are not in the lease. You may even run afoul of HOA covenants and restrictions.
Make sure you have a well-written lease. A lawyer is your best bet if you're not working with a property management company.