How can I get a previous tenant to pay rent they owe in Colorado without a lease or security deposit?

I didn't have a lease with the tenant but I do have a history of them paying me for a couple of years until they left without notice. I did not provide the tenant with a wirtten demand for payment of the past rent until they had been gone for over 30 days. In addition to not paying the last month's rent, I had to do quite a bit of repairs to the house to get it back into rental condition again. Can I go to small claims court without a written lease as evidence of the contract to show the judge and have a reasonable chance to get a judgement against the tenant? The Tenant is claiming that she didn't pay the last month's rent because she provided me with daycare services for my son over a two month period leading up to her departure. She says that my husband said to her that I would offset the last month's rent in exchange for the daycare. If I do get a judgement, how hard is it to collect on it?

You may always sue, on a verbal rental, a history showing proof of prior payments is normally evidence.
You will need proof of the damages, photos and estimates of professionals showing the cost of the repair to sue for.

It will be up to the judge to believe or not believe their story of baby sitting,

And getting a judgement is the easy part, if you live in a area that allows a garnishment, you will have to find where they work ( if they do) and find bank accounts ( do you have records showing what bank they paid you from.

Yes, you can sue. If they lived there for an extended period, then you should have ample evidence of the rental. Did your husband , in fact, offer to barter baby sitting services for rent? If so, then you deduct that from what you are suing for. If you think she can prove that she did watch the child, then I would still deduct that.

The problem is,m even if you win, you will have to collect on the judgement.