You have all raised some interesting reasons why the OP should keep his Mass DL. However, with respect to Florida, a person may file a declaration of domicile as follows:
http://www.miami-dadeclerk.com/property_recorder_domicile.asp
Florida Statute §222.17 states that a person can show intent to maintain a Florida residence as a permanent home by filing a sworn Declaration of Domicile with the clerk of the circuit court.
The application is available
online , at any of the
district courts or at the County Recorder's Office. Click the form, a person does not need to spend a certain number of days in Florida. They only need to obtain a Florida drivers license and register to vote to be a legal Florida resident. I am not sure that Mass can stop that. Of course a person working in Mass even as non resident must pay mass income tax, but that is it.
or from another county:
FAQ: Recording: Declaration of Domicile - Clerk & Comptroller, Palm Beach County
Now, the OP replied and I understand his reasons. They make sense for his particular situtation. However, for all who are falling all over themselves to keep a Mass DL even if they have a home elsewhere it is not required. The Florida declaration of domicile was instituted back when Florida had an intangibles tax (which has since been repealed) but would cost folks far less than paying resident income taxes in NY or NJ. People would file the form and pay Florida instead of high tax northeastern states. Since that intangibles tax was repealed, a Florida residence is even more valuable.