Centennial Rental -how to not renew the lease

[Marysue Connelly]

I have a rental home in Centennial, Co (couldn't find Centennial on the Colorado city options).  I currently have a single mom in the property .  She originally moved in 6 years ago as a couple w/ 2 children,  they got a divorce last year and she stayed in the house.  She pays the rent on time but is generally difficult to deal with.  She makes it very tough to get in and do any repairs even though she likes to complain about things.  I want to not renew the lease.  Is there anything specific I need to consider regarding rental laws in Colorado or Centennial?  Can I just give 90 days notice we won't be renewing the lease, no reason necessary?