I wear a full face helmet. You'll really appreciate one crossing through the Everglades on Tamiami Trail (old US 41) on your way to the Keys. Don't know how they get around that big RSTD windshield, but i get an average of 5 loud cracks on the helmet from the variety of large hard shell flying insects on that 80 mile stretch depending on the time of day and every time I think I'm glad that's not my head getting hit at 60 with that bug.
If it was only me I had to worry about I probably wouldn't wear one, but that is not the case. Have gotten so used to it, Its difficult for me to ride without one now.
Don't have to wear a helmet in Florida, but insurance is required to not wear a helmet.
I don't think you can or should legislate common sense. Someone told me a long time ago-- If your gonna be dumb, you gotta be tough.....
RSTDdog