Residency in any particular state is a matter of facts and circumstances beyond what an individual state mandates residents do. Often times residency can be dependent solely on intent.
A preponderance of facts will determine in which state a person is considered a resident. Some of those facts include but are not limited to the following:
Where is most of their time spent
Where do they have a driver's license or government issued ID
Where does their mail go
Where is their car registered
Where are they registered to vote
What do their insurance policies state
What do their tax returns state
Even if everything indicates you are creating residency in FL but you do not have such intent or no intent to surrender your NY residency, you may still be considered a non-resident of FL and a resident of NY.
It also matters why you are trying to determine your residency. Most states have varying degrees of time before certain actions need to be taken; for example surrendering your old state's driver's license and obtaining a new one in your new state or registering your car in your new state.
For certain state benefits, like in-state tuition rates, the time period and requirements can be much longer and more difficult.
