We have a South Dakota RV domicile, but we have recently purchased a house in Colorado. We are retirees and have no employment income or real estate income. Can we keep our SD residency benefits and driver's licenses or do we have to get CO driver's licenses and register our vehicles in CO?

Hello T:

You must register your vehicles and get drivers licenses from the state in which you reside. That would be Colorado.

excon

You may have two domiciles, and decide which one is your primary residence.
For IRS purposes, it's the one where you spend the most time. That can be by one day if you want.
There are other definitions of primary residence. One of the tricky ones is vehicle registration. Most states don't let you live there more than a few days without registering, and if your insurance finds out you are living elsewhere than your address on file, they can make it difficult to win a claim. But you don't want to keep re-registering as you go back and forth, so pick one state.
Other definitions have to do with voting, and sometimes local taxes, probably like the one you mention (a senior residential deduction, perhaps).
Pick one.

Just to reinforce what the others have said, being in a similar situation myself:

You have one "principal abode," but may have two or more residences. Think of the principal abode as "home" and the other as "vacation property." In general your principal abode is the place where you spend the most time each year. But other factors may influence this - if for example you plan on keeping the house in CO for only a couple of years and then moving back full time to SD then SD may be considered your principe abode even if you currently spend more time in CO. Other factors such as social clubs you belong to, mailing address for social security and other financial statements, where you are registered to vote, etc can all be factors. Given that CO has an income tax whereas SD does not, I'm guessing you're trying to figure out whether you can keep SD as your principal abode for tax reasons even if you spend more time in CO - is that rigt? If so, give us a few more details on time you plan to spend in each state and your longer-term intent and we can help you figure it out.

Once you figure out where your principal abode is, next step is to make sure your driver's license is in agreement, and register to vote accordingly.

As for car registrations: if you drive back and forth from SD to CO I suggest having the car registered in the state of yor principal abode. But if you keep vehicles at both properties, then register each in its home state. You will need two auto insurance policies - not a big deal as all national insurance companies handle this all the time.