Hopefully, this goes without saying, but you may only vote once – and from just one location. If you own homes and spend time living in two different states, vote from the state you identify as “home,” or the state in which you spend the greatest amount of time. For instance if you have a permanent home in New York to which you return each spring after spending just three months of the year in Florida, then you would vote in New York.
If you spend equal amounts of time in both homes and are otherwise eligible to vote in both states, then you can choose ONE state to vote in, and you should stick with that state (ie. you should not vote in one state this year, and then decide to vote in the other state two years from now).
Generally, residency is defined as presence within the jurisdiction and the intention to be a resident of the jurisdiction (in other words, the intent to stay), so let that guide you in making your decision.