[retiredguy123]

Originally Posted by biker59

A lot of factors go into this decision. One of them is tax law in each state: one could be legally a resident of two different states depending on their rules, so check this with your tax preparer. It is rarely a case that, for tax purposes, one gets to choose which state they declare as their residence; it's a matter of counting days and seeing if you meet that test.
As I recall, income from sources such as pension, Social Security (if taxed), interest, capital gains, etc., all go with the location of the taxpayer. Timing may also matter: When I moved from MD, I took my IRA withdrawals after the move to avoid MD tax. Income from real property and other sources that are fixed is taxed in the state of the property; e.g., unemployment paid by a state.
Another, as others have mentioned, is the homestead exemption, which lowers property tax. If you switch to FL you pay lower tax here, but you pay in turn pay higher tax in CO; check the rules there.
A third is the home sale exclusion on Federal taxes. You can exclude up to $250000 of gain ($500000 if filing jointly) if the home that was sold was your primary home for 2 of the preceding 5 years before the sale. If you change residence to FL, that starts the clock on the CO home. So if you don't plan to sell it within 5 years, you start to lose some of the exclusion.
Some things to consider.

As I understand the exclusion rule, if you move from Colorado to Florida, you would only have 3 years sell the Colorado house and qualify for the 2 out 5 year primary residence rule requirement. And, you either qualify for the entire exclusion or none of it. You cannot get some of it.