Once I terminate my lease, will I owe the landlord any money?
You could owe the landlord an amount equal to one month’s rent if the landlord has lost money due to your early termination. The landlord must document this money (damages) that s/he lost. This payment to the landlord would be due within 90 days of leaving (vacating) your home. The landlord can keep your security deposit until you pay that one month’s rent or the landlord can use your security deposit to off-set the money you would owe him/her.1
What often happens is that the landlord holds onto the security deposit and returns it if s/he is able to quickly re-rent the apartment/house and if the security deposit isn’t needed to repair physical damage to the unit. If the landlord cannot quickly re-rent the apartment/house, s/he keeps the security deposit in lieu of the rent payment due.
1 Colo. Rev. Stat. § 38-12-402(2)(b)